diy water filtration experiment

Make a water filter

This fun science experiment turns dirty water clean. (Kind of.)

How do you clean up dirty water?

Not with soap! You need a filter, a device that removes impurities, like dirt, from water. The filter you’ll make here—with the help of an adult—is a super strainer, and it’ll help you clean up your act.

Ask a grown-up to cut the bottle in half. Then flip the bottle's top half over and put it in the bottom, so the top looks like a funnel. You'll build your filter in the top part.

Place the coffee filter (or bandanna, sock, etc.) at the bottom of your filter.

Add cotton balls, charcoal, gravel, sand, and / or other materials in layers. You can use just one of them or all of them. Tip: Think about which order to add them. Bigger filter materials usually catch bigger impurities.

Write down which filter materials you used and in what order you layered them.

Stir your dirty water and measure out a cup of it.

Get your timer ready!

Pour a cup of dirty water into your filter. Start the timer as soon as you begin pouring.

Time how long it takes for all the water to go through the filter. Then write down how long it took.

Carefully scoop out the filter materials, one layer at a time. What did each layer take out of the water?

Experiment! Clean the bottle and try again. Put the filter materials in a different order each time, and time each experiment. What do you discover?

WHAT'S GOING ON?

The slower, the better! The longer it takes for water to move through a filter, the cleaner it gets. Water slips easily through the filter materials, but bigger gunk, like dirt, gets trapped. The filter materials usually get finer and finer, so they can catch whatever was missed earlier. Activated charcoal can be near the end of the water’s path, because it uses an electrical charge to grab particles too small for us to see.

Your filtered water is not clean enough to drink. But a plant will love it!

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1. Create a dirty water sample

2. build your filter cartridge, 3. design your filter, 4. test and evaluate the results, 5. revise and try, try again.

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Make a Water Filter

Design and build a device that can clean a dirty water sample using materials around your home. You’ll follow the same design process used by NASA engineers and scientists when they developed the water filtration system for the International Space Station orbiting Earth. To do so, you’ll use an iterative process, meaning you’ll test multiple designs, look at how your materials get you closer to your goal, and record your findings to build the best filter possible.

Important safety note!  This activity is not designed to make drinkable water. No matter how “clean” your filtered water looks, you should never drink it because it still may contain pollutants you can’t see.

› Educators, explore how to turn this into a standards-aligned lesson for students

Watch the tutorial.

See below for materials and step-by-step instructions. For more video tutorials and activities like this one, visit Learning Space .

Watch en Español : Seleccione subtítulos en Español bajo el ícono de configuración.

In this episode of Learning Space, you'll use materials from around your home to build a device that can clean a dirty water sample like the water filtration system on the International Space Station. | Watch on YouTube

1-2 empty plastic water bottles

Towel or paper towels (for spill clean up)

Cheesecloth or gauze to cover the mouth of the bottle

Rubber bands

Any materials you think will make a great filter (cotton balls, sand or gravel, uncooked pasta noodles, coffee filters, etc.)

*Don’t worry if you don’t have all of the materials. Get creative and substitute materials with what you have! It’s all part of the design process.

Start by preparing the water you’re going to filter. This can be done in many ways that change how difficult it is to filter the water. For example, mix some soil or dirt with tap water for an easier challenge. Try also adding food coloring or vinegar for a bigger challenge.

This dirty water sample will simulate wastewater. On the space station, this wastewater is made up of everything from the fuel that powers the station to astronauts’ sweat.

Until a few years ago, water needed to sent up to the space station in large containers the size of duffel bags. But in 2010, a filtration system was installed that made it so that water could be cleaned and reused onboard the space station.

To build your own filtration system, you’ll need a filter cartridge. Start by carefully cutting your water bottle in half, across the width of the bottle. Remove the cap from the bottle. Put gauze or cheesecloth over the opening and secure it with a rubber band. Turn the top half of the bottle upside down (so the part with the cheesecloth or gauze is facing down) and place it into the bottom half of the bottle.

If you want to fit more materials in your filter, you can use two bottles. You can also use larger bottles or try other containers. Note: Clear containers will help you see the filtration as it takes place.

The filtration system on the space station has several stages that first filter out larger debris, then smaller impurities and even bacteria. You may want to use similar layers in your filter.

Mix or layer the filter materials you’ve collected in the top of your filter cartridge. Write down what filtration materials you use and how much.

Pour your simulated wastewater into your filter and observe the water that comes out at the bottom of the filter. How effective was your filter at cleaning the water? Write down what you notice. How long did it take to filter the water? What worked well? What could be improved?

Important safety note! No matter how “clean” your filtered water looks, you should never drink it because it still may contain pollutants you can’t see.

Revise your filter based on what you saw during the last step. Then, test it again. Consider using the same amount of wastewater for each test so you can better evaluate how well your filter is working not just in terms of the color of your filtered water, but how much you’re able to clean, or reclaim.

The filtration system on the space station reclaims 93% of the water onboard. Every drop counts!

As you revise, you’ll find that some filter materials work better than others – not just at filtering out solids like dirt, but also in removing colors. Keep redesigning and testing your filter. Your goal is to produce as much clean water as possible during a single time through the filter.

Remember: Do not drink the dirty or filtered water!

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How to Make a Homemade DIY Water Filter

Want to filter your water in the wilderness, make your own emergency preparedness solution, or just get stuck into a fun project with the kids?

In this guide, we’ve shared the process that we personally used to make a highly effective DIY water filter, using just a few simple tools and natural filter media. 

Note: There are a few different methods of making DIY water filters, and several types of materials you can use. We’re sharing instructions for the filter we personally made ourselves, which uses multiple layers of filtration, including gravel, sand, and activated charcoal, to remove various impurities from water. 

Table of Contents

📲 Video Guide

📝 what you’ll need, ✂️ step 1: cut the bottom off the plastic bottle, 🔄 step 2: flip the bottle, ☁️ step 3: add the first material to the bottle, 🔮 step 4: prepare & add the charcoal, 📥 step 5: add a layer of fine sand, 📤 step 6: add coarse sand on top, 🪨 step 7: top with gravel, 🔲 step 8 (optional): add a top strainer, 🔎 test it out, 🔂 a note on double filtering, 📑 final word.

You will need: 

• A plastic bottle
• Gravel of different sizes
• Sand, both fine and coarse, if possible
• Cotton, bandana, sock, or similar
• Activated charcoal

Take the plastic bottle and cut the bottom inch or so off, using a knife. 

Next, remove the cap from the bottle (if you haven’t already), or, if you plan to use a coffee filter in step 3, stab a hole in the lid using a knife or a sharp pair of scissors. We removed the cap as we used cotton balls in step 3 instead. 

Flip the top of the bottle upside down and place it in the separated bottom for stability, with the cap end pointing down. This will prevent the bottle from tipping over when you add your filter materials.

Now you can start adding materials into the bottle. 

The first material, which will go at the bottom, needs to be able to hold everything else above it.

If you have them, cotton balls work great for this purpose. You can also place a coffee filter over the bottle opening, so that the excess material of the filter overlaps around the bottle’s sides. Then, put on the lid and tighten it to secure the cap.

If you’re in a survival situation, anything made of cloth, like a bandana or even a sock, will work just fine.

The next material you’ll add is charcoal. 

If needed, break down the charcoal into small pieces (we found it easiest to use a hammer, but you could also use a rock). You want to fill as much of the bottle’s surface area with the charcoal as possible. 

You can now pour the charcoal on top of the first layer. This layer should be about 1 inch in thickness. 

Next, add a layer of sand. Any sand is fine, but the finer and smaller the grains, the better – fine sand should be able to remove smaller contaminants from your water .

Also don’t use processed, dyed craft sand, which could introduce chemicals into your water.

Again, this layer of sand should be around 1-inch thick . 

If you can find it, add a 1-inch layer of coarse sand on top of the fine sand. 

In our own experience making this filter, we found that using both coarse and fine-grained sand means you can filter water through two separate textures, allowing for more diverse, thorough filtration. 

Pour gravel into the bottle, stopping once the top surface of the gravel is one inch away from the cut part of the bottle. 

Again, you can use both chunky and fine-grained gravel here to provide separate layers of filtration.

Lastly, if you have the resources, cover the top layer with a coffee filter or a cloth (such as a cheese cloth or bandana). 

This is an optional step but it’s great for straining large debris from water.

Your filter is now ready to test. For this, grab a clean cup or use the bottom of the water bottle you already cut off to catch the filtered water.

Carefully pour your dirty water into the top of the filter and watch it work its magic.

Our Tip: Slow, steady pouring is best. Pause between adding water to wait for the water level to fall below the top of the gravel.

Water will travel through the filter layers, becoming cleaner as it goes. Within a few minutes, it’ll start to fill the bottle.

If you have a dirty or turbid water supply, you might need to filter water several times through your bottle filter. 

To do this, wait for all the water to fill the cup, then put the water bottle onto another cup and pour your original batch of water back through the bottle.

We’ve tried a few different DIY water filters, and we’ve found that in our testing, this one worked best. 

It’s important to keep in mind that while this homemade filter can remove some impurities, it’s not a guaranteed replacement for commercial water filters or municipal water treatment. There’s also no way to know for certain that the filter has removed certain contaminants from your water unless you conduct before-and-after water quality testing. 

So if you’re relying on this for drinking water and you’re using a water source that’s potentially microbiologically contaminated, you’ll need to boil the water for three minutes to make it potable (safe to drink) after you’ve filtered out the contaminants . That’s because microorganisms like bacteria are too small to be trapped in any of these homemade water filter materials.

If boiling isn’t an option, you can also chemically disinfect your water with iodine tablets or unscented bleach, or sterilize it using UV. 

Continue Reading:

• Don’t know where to start? Learn all about How to Filter Water at Home or In the Wilderness
• Learn How to Make Your Own Whole House Filtration System
• Want to buy an on-demand system instead? See Our Review of the Top Water Filters Money Can Buy
• On a small budget? Check out our List of the Best Affordable Water Pitchers here!

Brian Campbell, a WQA Certified Water Specialist (CWS) and Certified Water Treatment Representative (CWR) with 5+ years of experience, helps homeowners navigate the world of water treatment. After honing his skills at Hach Company, he founded his business to empower homeowners with the knowledge and tools to achieve safe, healthy water. Brian's tested countless devices, from simple pitchers to complex systems, helping his readers find the perfect fit for their unique needs.

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Water Purification Science Project + video

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Water covers two-thirds of the Earth's surface and makes up about 60% of adult's bodies, including 75% of our brains!

Each day, it is recommended that we consume more than two liters of drinking water / purified water. And thanks to professionals that work in public health to ensure we have a safe drinking water supply without impurities, we can all drink to meet these needs.

Although there's plenty of sources of water on our planet, our water supply in terms of drinking water / clean water isn't as readily available to drink. (e.g., frozen in glaciers or ocean water). Even if it's fresh water, it may contain waterborne diseases and or be contaminated water.

Water treatment science and advanced water systems enable us to purify dirty water so it's safe for our purposes. Let's conduct a water purification project to better understand our water sources, water purification systems, and general water resources. This type of experiment is a perfect science fair project for either middle school or elementary school students!

CAUTION: Adult supervision is required when handling chemicals and/or cutting objects. Remember to use proper safety equipment when experimenting.

Because we won't disinfect our water sample for this water project and will just be making an example water filtration system, it is NOT safe to drink as this purification process and treatment process we will experiment with will not provide safe and pure water.

Science Experiment: Build a Water Treatment System

What you need:.

• 1/2 L of swamp water or tap water with mud or dirt added (the water quality is not important)
• 2 L soda bottle/plastic bottle with its lid
• 2 L plastic soda bottle—cut in half (have an adult help with cutting)
• 1000 ml beaker
• 2 20 oz plastic cups
• 1 tbsp alum (aluminum potassium sulfate)
• 2 c fine sand
• 1 c coarse sand
• 1 c small pebbles
• 1 filter paper or coffee filter (to help serve as a water filter)
• 1 rubber band
• 1 large spoon for stirring
• spoon for scooping the alum
• stopwatch or timer

DIY Water Filtration System for Science Project

• Pour swamp water in the 2-liter bottle with a lid. Notice how it looks and smells.
• Put the lid on the bottle and shake vigorously for 30 seconds. Then pour the water back and forth between the two cups about 10 times.
• Pour the water into the bottle with its top cut off. Again notice how the water looks and smells.
• Add 2 tablespoons of alum to the water in the bottle with the top cut off. Use the spoon to slowly stir the water for five minutes. What do you notice about the water as you stir it?
• Now let the water sit undisturbed for 20 minutes, checking it every five minutes to note how it looks and smells (without moving it).
• Use a rubber band to secure the filter paper to the mouth of the bottle with its bottom cut off. Put it upside down in the beaker.
• Pour the pebbles into the bottle. Then pour the coarse sand on top of the pebbles and the fine sand on top of the coarse sand.
• Carefully pour about two liters of clean tap water through, being careful not to disturb the top layer of sand. Pour the rinsed water out of the beaker.
• Pour the top 2/3 of the swamp water through the filter, taking care to leave the sediment in the swamp water bottle.
• Once all the water has passed through the filter, compare the swamp water with contaminants to the filtered water. How do they look and smell different?

What happened:

There are five steps to basic water purification: aeration, coagulation, sedimentation, filtration, and disinfection.

Our project took us through the first four.

Aeration adds air to the water. It allows gases trapped in the water to escape and adds oxygen to the water.

Coagulation is the process that allows dirt and other suspended solid particles to chemically stick together (clumps of alum and sediment). During this step, the water is also purified or made clear and colorless.

Sedimentation is the process that occurs when gravity pulls the particles to the bottom of the container. So as the water sits undisturbed, most of the floc settles, preparing the water for the next step.

Filtration is the process where the remaining solid smaller particles and floc are separated and removed from the water.

Disinfection is the final step, in which water is chemically treated to remove bacteria, pathogens, and other micro-organisms. These unseen bacteria can cause severe sickness and even death in humans.

Because we didn't disinfect our water, it is NOT safe to drink.

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Homemade Water Filter Experiment

July 6, 2019 By Emma Vanstone 11 Comments

Today we are looking at filtering and how it can be used to clean dirty water. This water filter science project is very simplified but gives kids a great overview of how water purification is carried out to give us lovely clean drinking water.

Do not drink the water in the activity

Water Filter Science Project

Filtering water – what you need.

Dirty water ( or mud and clean water )

Coffee filter/paper towel/muslin

An empty bottle or other containers

Filtering Water Experiment

The great thing about this experiment is that you can design it however you like.

We set up coffee filters containing sand, stones and then just plain filters.

We carefully poured the same amount of water through each filter and observed the results.

More ideas to try – Water Filter Science Project

Set up an experiment where the conditions are:

1 coffee filter

2 coffee filters

3 coffee filters

Is kitchen roll better than a coffee filter, would just a sieve work?

You could also work in stages, so try a colander, then a sieve and then a paper towel. Each stage should trap smaller and smaller particles.

How do filters work?

A filter is a porous material which a liquid can be passed though to separate the liquid from solids suspended in it.

More Filtering Investigations

Make a toy filter .

Try filtering potions using a sieve and colander.

Can you filter water using sand and stones ?

More Science for Kids

I’ve got a fun collection of water science experiments , including a water cycle activity, dissolving experiment, ice investigation and density trick!

Try one of our easy science experiments for kids to do at home ! We’ve got egg experiments, ice experiments, paper helicopters, STEM challenges and lots more science fun for kids of all ages!

Suitable for Key stage 2 Science

Properties and Changes of Materials

Use knowledge of solids, liquids and gases to decide how mixtures might be separated, including through filtering, sieving and evaporating.

Last Updated on August 6, 2024 by Emma Vanstone

Safety Notice

Science Sparks ( Wild Sparks Enterprises Ltd ) are not liable for the actions of activity of any person who uses the information in this resource or in any of the suggested further resources. Science Sparks assume no liability with regard to injuries or damage to property that may occur as a result of using the information and carrying out the practical activities contained in this resource or in any of the suggested further resources.

These activities are designed to be carried out by children working with a parent, guardian or other appropriate adult. The adult involved is fully responsible for ensuring that the activities are carried out safely.

Reader Interactions

May 15, 2012 at 11:49 pm

This is such a neat experiment. I bet it would be fun to let the kids think of better ways to filter the water. It will definitely give them a better appreciation for our clean water!

May 18, 2012 at 8:22 pm

So simple, and yet so fun! A very good way to learn about filters and clean water. We will definitely have to try this one, thanks 🙂

May 22, 2012 at 8:21 pm

We did that once too and it’s amazing how much gets filtered out and how gross that water still is. I think yours was more easily visble, we have very clay like dirt, so it didn’t quite dissolve right. Thanks for linking up to Science Sunday!

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• Water Filters

How to Make a Water Filter

Last Updated: June 26, 2024 Fact Checked

wikiHow is a “wiki,” similar to Wikipedia, which means that many of our articles are co-written by multiple authors. To create this article, 121 people, some anonymous, worked to edit and improve it over time. This article has been fact-checked, ensuring the accuracy of any cited facts and confirming the authority of its sources. This article has been viewed 1,198,768 times. Learn more...

Water is essential to life. This technique is very useful when you are hunting to survive. People can live up to a week without food, but only two to three days without water. Clean water can be hard to find if you get stranded in the wild or if there is an emergency. If you have to find your own water supply, you must be able to strain out impurities that can make you sick. This article will tell you how to make a water filter.

Making a Water Filter

• Plastic bottle with a cap
• Craft knife
• Hammer and nail
• Coffee filter
• Large cup or mug (Either one works)
• Activated charcoal
• Container to catch the water (jar, cup, mug, etc)
• If you are a child, ask an adult to help you with this step
• Add handle so that you can hang it while it filters the water. Start by poking two holes near the cut edge of the bottle. Make the holes opposite of each other. Thread a piece of string through the two holes. Tie the string in a knot.
• Charcoal can get very dirty. You can keep your hands clean by wearing some gloves.
• Try using two types of sand: a fine grained sand and a coarse grained sand. The finer sand will go first, on top of the charcoal. The coarse grained sand will go next, on top of the fine-grained sand. This will create more layers for the water to pass through, and help make it cleaner.
• Try using two types of gravel: a fine grained gravel and a chunky gravel. The fine grained gravel will go first, on top of the sand. The chunky gravel will go next, on top of the fine gravel.

Using Your Water Filter

• If you are higher than 5,000 feet (1,000 meters) above sea-level, you will need to boil the water for at least three minutes. [7] X Trustworthy Source United States Environmental Protection Agency Independent U.S. government agency responsible for promoting safe environmental practices Go to source

Making Other Types of Filters

• If you don't have a coffee filter, use a paper towel or a piece of cotton fabric instead. Make sure that the square is big enough to fit over the mouth of the cup. Try to use white fabric or a blank paper towel. Colored fabrics and paper towels contain dyes, which may bleed into the water.
• Cut a 4 inch (10.16 centimeters) long piece from a pine tree branch.
• Peel off the bark, and make sure that it can fit into the neck of the bottle. If it is too wide, shave it down using sandpaper or a pocket knife.
• Slide the first inch (2.54 centimeters) or so of the stick into the neck of the bottle.
• Cut the bottom of the bottle off and turn the bottle upside down.
• Fill the bottle with water, and let the water drain through the stick.
• Do not let the stick dry out. If it dries out, it won't be as effective. [11] X Trustworthy Source PLOS ONE Online peer-reviewed, open access scientific research journal Go to source

Community Q&A

• If the boiled water tastes flat, try adding a pinch of salt. You can also pour the water back and forth between two, clean containers a few times. [12] X Trustworthy Source United States Environmental Protection Agency Independent U.S. government agency responsible for promoting safe environmental practices Go to source Thanks Helpful 0 Not Helpful 0
• If you can't find a coffee filter, try using crumpled cotton fabric, or some pillow/teddy bear stuffing. Thanks Helpful 3 Not Helpful 0
• Rather than making a filter with a thick layer of charcoal, sand, and gravel, try making a filter with many thin layers of charcoal, sand, and gravel. Keep repeating these layers until you reach the rim of the bottle. Thanks Helpful 2 Not Helpful 0

• Filtering water does not make it safe to drink. Always purify the water before using it for drinking, cleaning, and preparing food. Thanks Helpful 3 Not Helpful 0
• Always boil your filtered water before using it for brushing teeth, cooking, drinking, making drinks (ie: coffee or tea), and washing dishes. [13] X Trustworthy Source United States Environmental Protection Agency Independent U.S. government agency responsible for promoting safe environmental practices Go to source Thanks Helpful 0 Not Helpful 0

You Might Also Like

• ↑ https://extension.usu.edu/waterquality/files-ou/Lesson-Plans/Homemade-water-purifier.pdf
• ↑ https://www.jpl.nasa.gov/edu/learn/project/make-a-water-filter/
• ↑ https://www.epa.gov/ground-water-and-drinking-water/emergency-disinfection-drinking-water
• ↑ https://iopscience.iop.org/article/10.1088/1742-6596/1349/1/012011
• ↑ https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0089934
• ↑ https://www.technologyreview.com/2013/10/24/175624/how-to-build-a-plant-xylem-water-filter/

About This Article

To make your own water filter, use a craft knife to cut the bottom inch off of a plastic bottle, then punch a hole in the bottle cap with a hammer and a nail. Place a coffee filter over the mouth of the bottle and tighten the cap over it, then put the bottle upside-down into a mug or cup. Fill the bottom third of the bottle with activated charcoal, the middle third with sand, and the top third with gravel. To use the filter, pour water into the bottle and let it drip through the hole in the cap. Read on to learn how to make a filter out of a coffee filter and a banana peel! Did this summary help you? Yes No

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• Why We’re Unique

Water Filtration

Introduction: (initial observation).

Humans may live for a month or more without food, but only a few days without water; only oxygen is more important. Each day, the body loses up to three quarts of water. A loss of only 10-20% of the body’s water content could be fatal.

When we take untreated water from a river or reservoir, the water often contains natural wastes and pollutants, such as bacteria, solids ( like mud, sand, and debris), inorganic minerals, and decayed organic compounds, as well as trace amounts of certain other contaminants. Such water is not good for human consumption.

Water suppliers transfer this water to a treatment plant where water will be filtered and chemically treated to be ready for human use.

People who have a water well at home, do a similar process in smaller scale and filter their own water.

There are also companies who offer varieties of filtration systems for home.

This project guide contains information that you need in order to start your project. If you have any questions or need more support about this project, click on the “ Ask Question ” button on the top of this page to send me a message.

If you are new in doing science project, click on “ How to Start ” in the main page. There you will find helpful links that describe different types of science projects, scientific method, variables, hypothesis, graph, abstract and all other general basics that you need to know.  

Project advisor

Information Gathering:

There are many government organizations who research, control and offer information about water and water treatment. Food and drug administration (FDA) and Department of environmental protection (DEP) are among the best sources for information. Also many universities continuously research and offer courses about water filtration and treatment.

Following links are recommended for additional information.

• US Environmental Protection Agency (Office of Water)
• History of drinking water treatment (PDF)
• Water testing Scams
• Encyclopedia of Water Terms
• Home water treatment options
• Available Filtration Technologies

What are the impurities in water?

Water impurities are:

• Solids (Like mud, sand, debris, pollen, mold, fungal spores, dust mites, algae, cockroach dust, ..).
• Inorganic Minerals dissolved in water such as Calcium and Magnesium Salts.
• Decayed organic compounds from dead plants and animals and animal waste. These are the impurities that give a bad taste and odor to the water.

What are the sources of impurities?

• Wildlife that inhabits the water and the surrounding lands are a main cause of water contamination. Small animals such as fish, frog and insects excrete waste material from their bodies to the water.
• Mines and exposed acid producing minerals.

How each impurity is removed?

• Paper or fabric filters separate solid impurities such as mud, sand and dust.
• Ceramic or sand filters separate much of organic impurities from plants and animals. In municipal water treatment plants this separation is done by settling the organic material using Alum or Aluminum Sulfate.
• Carbon block filter removes oils, benzene, herbicides, pesticides and other volatile organic hydrocarbons.
• Granular activated carbon removes chemicals that cause bad taste and odors.

What is water treatment?

Water treatment is disinfection of water by killing disease causing virus, bacteria and parasites.

Water treatment is done by adding chlorine, ozone or using Ultra Violet light.

• Chlorine gas kills bacteria with adequate contact time.
• Ozone units super-oxygenate water which kills bacteria with adequate contact time.
• Ultraviolet light systems make use of the ability of this portion of the light spectrum to kill bacteria. Such systems are only effective on bacteria, viruses and some algae.

Using sand, ceramics and charcoal to filter water is a slow process and is not economical for large amount of water, that is why all water suppliers are using methods other than filtration.

What do water treatment facilities do?

Water treatment facilities purify large amount of water in large tanks using the following three steps.

First material floated on the water will be separated (Using steel mesh) Then other impurities will be settled slowly and by adding chemicals Finally Chlorine will be added for disinfection.

Question/ Purpose:

The purpose of this project is to learn about filtration, what it does and how it works. This project will also help us to know the difference between filtration and treatment.

Some of the specific questions that can be studies for this project are:

• How does the height of charcoal layer in a filter affect the rate in which organic impurities will be absorbed?
• How does the size of charcoal pieces in a filter affect the rate in which organic impurities will be absorbed?

Identify Variables:

When you think you know what variables may be involved, think about ways to change one at a time. If you change more than one at a time, you will not know what variable is causing your observation. Sometimes variables are linked and work together to cause something. At first, try to choose variables that you think act independently of each other.

If you are doing this project as a display project, you can skip this section. However, if you are doing this as an experimental project, then you will need to come up with questions, write your hypothesis, identify variables and do experiments to test your hypothesis.

For the above two questions that we have proposed, this is how you define variables.

• The height of charcoal layer is an independent variable (manipulated variable). The rate in which organic substances are absorbed is the dependent variable. Controlled variables are: Size of filter, concentration and type of pollutants, order and amount of filter material.
• The size of charcoal pieces is an independent variable (manipulated variable). The rate in which organic substances are absorbed is the dependent variable. Controlled variables are: Size of filter, concentration and type of pollutants, order and amount of filter material.

Hypothesis:

Based on your gathered information, make an educated guess about what types of things affect the system you are working with. Identifying variables is necessary before you can make a hypothesis. Following are two sample hypothesis for two questions suggested above.

• By increase in the height of charcoal layer, the rate of filtration of organic material will increase.
• Smaller size charcoal can result a higher rate of filtration. Large piece of charcoals may have no filtering affects at all.

Experiment Design:

Design an experiment to test each hypothesis. Make a step-by-step list of what you will do to answer each question. This list is called an experimental procedure. For an experiment to give answers you can trust, it must have a “control.” A control is an additional experimental trial or run. It is a separate experiment, done exactly like the others. The only difference is that no experimental variables are changed. A control is a neutral “reference point” for comparison that allows you to see what changing a variable does by comparing it to not changing anything. Dependable controls are sometimes very hard to develop. They can be the hardest part of a project. Without a control you cannot be sure that changing the variable causes your observations. A series of experiments that includes a control is called a “controlled experiment.”

Experiment 1: Experiment with filters

Material Needed:

• 2-liter soda bottle, cut and dispose 2 inches from the bottom (by an adult)
• napkins or paper towels
• gravel, sand and cotton balls for your filter
• Charcoal (Cheapest one that don’t have liquid fuel added and have no odors)
• dirty water, (If you cant find any, make it yourself)  Instructions:
• Put the the soda bottle upside-down (like a funnel) and secure it so it will remain that way. You may do it by making a stand for that or hang it from some place.
• Layer the filter materials inside the soda bottle. Think about what each material might remove from the dirty water and in what order you should layer the materials. For an added challenge, use one additional materials to build your filter.
• Pour the dirty water through the filter. What does the filtered water look like?
• Take the filter apart and look at the different layers. Can you tell what each material removed from the water?
• Wipe the bottle clean and try again. Try putting materials in different layers or using different amounts of materials.

Exact measurements of the layers are optional; however, they affect the quality and the price of your filter. For example you may use a lot of activated carbon in your filter. In this case your filter will be very good, but it will also become expensive. On the other hand if you use a lot of sand with no or little activated carbon, then your filter will not be good and it will be cheap.

Now it’s time to experiment. Think of a question you want answered. Like, are there better materials for cleaning water? Be sure to predict what you think is going to happen. Then, test it out using different materials and record the results for your report.

Other samples:

• Water Filter
• Water Plant tour

Following are sample images of water filtration experiment. Material used for filtration in these images are Fish tank charcoal, Sand, Gravel and Coffee Filter

Experiment 2:

Test the effect of charcoal layer on filtration of organic compounds.

• Mix some food coloring with water to simulate water polluted with organic material.
• Make 3 identical filters with different heights of charcoal layer.
• Filter two cups of the colored water that you have made with each of your three filters.
• Compare the color of three filtered waters and record the results. Visually determine the rate of filtration (or the rate of color loss) and write that in your results table.

Your results table may look like this:

Height of charcoal layer Rate of filtration

You may also use the above results table to draw a bar graph. 

Experiment 3: (Permittivity)

Compare the filtration time of different filter materials

Introduction:

In a multi-layer water filter, it takes certain amount of time for water to travel each layer. The total filtration time is the sum of the individual travel times for different layers. Travel time of water in each layer depends on how pores the materials are and the attraction forces between the molecules of water and the molecules of filter materials. In this experiment we compare some of the filtration materials for their speed of filtration also known as permittivity.

• Get 5 identical bottles. Fill each bottle with 100ml water and mark the water level.
• Get 5 identical funnels and place them on the bottles. Write the name of filter materials on the funnels or bottles.
• At the bottom of each funnel place a piece of plastic mesh or steel mesh (like those used in making sieves). This is used to hold the filter materials in place.
• Fill each funnel to half with different filtration materials. (Filtration materials may include sand, clay, activated carbon, or any other substance that may be used in filtration).
• To each funnel add some water to saturate the filtration materials. Wait about 5 minutes. Empty any water that are entered in bottles.
• Add 200ml water to each funnel.
• Record the time it takes for the first 100ml of water that leave the funnel and enter the bottle. Your data table may look like this:

Materials and Equipment:

Multi-layer filters are normally a cylindrical container with layers of filter material. Top layers usually separate large solids and debris from the water. Middle layers separate much finer impurities to create a clear water. Lower levels are usually activated carbon to separate hydrocarbons, gasoline, insecticides and impurities that cause bad taste and bad odor.

A typical filter may start with a layer of gravel at the bottom, and then large sand, fine sand, clay, activated carbon, fine sand again, and large sand on the top.

These filters can not separate all viruses, bacteria and other micro organisms. Micro organisms later must be destroyed using chlorine or other disinfectant material.

Since filter absorbs some micro organisms such as bacteria and viruses, these micro organisms will reproduce inside the filter and exit the filter in later uses. That’s why filter material must be renewed so often.

Some filters are made only from different types of sand.

Results of Experiment (Observation):

Experiments are often done in series. A series of experiments can be done by changing one variable a different amount each time. A series of experiments is made up of separate experimental “runs.” During each run you make a measurement of how much the variable affected the system under study. For each run, a different amount of change in the variable is used. This produces a different amount of response in the system. You measure this response, or record data, in a table for this purpose. This is considered “raw data” since it has not been processed or interpreted yet. When raw data gets processed mathematically, for example, it becomes results.

Calculations:

If you do any calculations for your project, make sure to write your calculations in this section of your report.

Summery of Results:

Summarize what happened. This can be in the form of a table of processed numerical data, or graphs. It could also be a written statement of what occurred during experiments.

It is from calculations using recorded data that tables and graphs are made. Studying tables and graphs, we can see trends that tell us how different variables cause our observations. Based on these trends, we can draw conclusions about the system under study. These conclusions help us confirm or deny our original hypothesis. Often, mathematical equations can be made from graphs. These equations allow us to predict how a change will affect the system without the need to do additional experiments. Advanced levels of experimental science rely heavily on graphical and mathematical analysis of data. At this level, science becomes even more interesting and powerful.

Conclusion:

Using the trends in your experimental data and your experimental observations, try to answer your original questions. Is your hypothesis correct? Now is the time to pull together what happened, and assess the experiments you did.

Related Questions & Answers:

What you have learned may allow you to answer other questions. Many questions are related. Several new questions may have occurred to you while doing experiments. You may now be able to understand or verify things that you discovered when gathering information for the project. Questions lead to more questions, which lead to additional hypothesis that need to be tested.

Possible Errors:

If you did not observe anything different than what happened with your control, the variable you changed may not affect the system you are investigating. If you did not observe a consistent, reproducible trend in your series of experimental runs there may be experimental errors affecting your results. The first thing to check is how you are making your measurements. Is the measurement method questionable or unreliable? Maybe you are reading a scale incorrectly, or maybe the measuring instrument is working erratically.If you determine that experimental errors are influencing your results, carefully rethink the design of your experiments. Review each step of the procedure to find sources of potential errors. If possible, have a scientist review the procedure with you. Sometimes the designer of an experiment can miss the obvious.

References:

List of Related links. http://poolplaza.com/pool-filters.shtml

http://phys4.harvard.edu/~wilson/Feroze_Ahmed/Sec_3.htm

http://www.cc.cc.ca.us/pfp/Pfpfilter.htm

http://www.orival.com/water.shtml

Related information

How does a water softener work.

We call water “hard” if it contains a lot of calcium or magnesium impurities dissolved in it. Hard water causes two problems: It can cause “scale” to form on the inside of pipes, water heaters, tea kettles and so on. The calcium and magnesium precipitate out of the water and stick to things. The scale doesn’t conduct heat well and it also reduces the flow through pipes. Eventually pipes can become completely clogged. It reacts with soap to form a sticky scum, and also reduces the soap’s ability to lather. Since most of us like to wash with soap, hard water makes bath-time or shower-time less enjoyable. The solution to hard water is either to filter the water by distillation or reverse osmosis to remove the calcium and magnesium, or to use a water softener. Filtration would be extremely expensive to use for all the water in a house, so a water softener is usually a less costly solution. The idea behind a water softener is simple. The calcium and magnesium ions in the water are replaced with sodium ions. Since sodium does not precipitate out in pipes or react badly with soap, both of the problems of hard water are eliminated. To do the ion replacement, the water in the house runs through a bed of small plastic beads or a chemical matrix called zeolite. The beads or zeolite are covered with sodium ions. As the water flows past the sodium ions, they swap places with the calcium and magnesium ions. Eventually the beads or zeolite contain nothing but calcium and magnesium and no sodium, and at this point they stop softening the water. It is now time to regenerate the beads or zeolite.Regeneration involves soaking the beads or zeolite in a stream of sodium ions. Salt is Sodium Chloride, so the water softener mixes up a very strong brine solution and flushes it through the zeolite or beads (this is why you load up a water softener with salt). The strong brine displaces all of the calcium and magnesium that has built up in the zeolite and replaces it again with sodium. The remaining brine plus all of the calcium and magnesium is flushed out through a drain pipe. Regeneration can create a lot of salty water.

What is “activated charcoal” and why is it used in filters?

Charcoal is carbon. Activated charcoal is charcoal that has millions of tiny pores between the carbon atoms. According to Encyclopedia Britannica, “The use of special manufacturing techniques results in highly porous charcoals that have surface areas of 300-2,000 square meters per gram. These so-called active, or activated, charcoals are widely used to adsorb odorous or colored substances from gases or liquids.” The word adsorb is important here. When a material adsorbs something, it means that it attaches to it by chemical attraction. The huge surface area of activated charcoal gives it countless bonding sites. When certain chemicals pass next to the carbon surface they attach to the surface and are trapped.

Activated charcoal is good at trapping other carbon-based impurities (“organic” chemicals), as well as things like chlorine. Many other chemicals are not attracted to carbon at all – sodium, nitrates, etc. – so they pass right through. This means that an activated charcoal filter will remove certain impurities while ignoring others. It also means that, once all of the bonding sites are filled, an activated charcoal filter stops working. At that point you must replace the filter.

Water Filters General Information Activated charcoal (activated carbon) filters have been used in homes to remove taste and odor. Taste and odor, although undesirable, are generally not considered unhealthy. In recent years, however, activated charcoal filters have been used to remove some of the contaminants that have been discovered in water supplies.

Activated charcoal is most effective at removing organic compounds such as volatile organic compounds, pesticides and benzene. It can also remove some metals, chlorine and radon. As with any treatment system, it cannot remove all possible drinking water contaminants.

Because activated charcoal systems are limited in the types of compounds they can effectively remove, it is essential that the homeowner determine which water contaminants are present before purchasing such a system. Anyone who suspects they have a water quality problem should first have their water analyzed by their local health department or a reputable laboratory. These analyses are costly, but worth the expense since they are necessary to determine the appropriate home treatment system and how best to operate such a system. A state or local health official can interpret water analysis results. Some laboratories may also provide this service.

Note that home water treatment is considered only a temporary solution. The best solutions to a contaminated drinking water problem are to either end the practices causing the contamination or change water sources. Activated charcoal is a black solid substance resembling granular or powdered charcoal. It is extremely porous with a very large surface area. Certain contaminants accumulate on the surface of the activated charcoal in a process called adsorption. The two main reasons that chemicals adsorb onto activated charcoal are a “dislike” of the water, and attraction to the activated charcoal. Many organic compounds, such as chlorinated and non- chlorinated solvents, gasoline, pesticides and tri-halo-methane can be adsorbed by activated charcoal. Activated charcoal is effective in removing chlorine and moderately effective in removing some heavy metals. Activated charcoal will also remove metals that are bound to organic molecules. It is important to note that charcoal is not necessarily the same as activated charcoal. Activated charcoal removes vastly more contaminants from water than does ordinary charcoal.

Home activated charcoal treatment systems are quite simple. The activated charcoal is normally packaged in filter cartridges that are inserted into the purification device. Water needing treatment passes through the cartridge, contacting the activated charcoal on its way to the faucet. Activated charcoal filters eventually become fouled with contaminants and lose their ability to adsorb pollutants. At this time, they need to be replaced. Activated charcoal treatment systems are typically point of use installed where they typically treat water used for drinking and cooking only. Activated charcoal filters can be placed on the end of the faucet, on the countertop, or under the sink. Point of use systems often have a bypass so that water for purposes other than drinking and cooking can also be dispensed at the tap without being treated. This increases the life of the activated charcoal, reducing the time between filter replacements.

A point of entry system is more appropriate if a contaminant is present that poses a health threat from general use as well as from consumption. Volatile organic compounds and radon are examples of this type of contaminant. These contaminants may get into the indoor air when water is used for showering and washing. In this case, it is more economical to have a large pint of entry system that treats water as it enters the home than to have point of use systems at each tap.

Activated charcoal filters used for home water treatment contain either granular activated charcoal or powdered block charcoal. The amount of activated charcoal in a filter is one of the most important characteristics affecting the amount and rate of pollutant removal. More charcoal in a cartridge means more capacity for chemical removal, resulting in longer cartridge lifetime. This means fewer cartridge changes and less chance of drinking contaminated water. Particle size will also affect the rate of removal; smaller activated charcoal particles generally show higher adsorption rates. Rust, scale, sand or other sediments can clog any activated charcoal filter. A solution to this problem is to place foam or cotton filters (often called sediment or fiber filters) between the cartridge and incoming water. When sediment filters become clogged, they need to be replaced or they will cause water pressure to drop.

An activated charcoal filter must be deep enough so that the pollutants will adsorb to the activated charcoal in the time it takes the water to move through the filter. The appropriate filter depth depends on the flow rate of water through the filter. The slower the flow rate, the better the removal. The poor performance of some end of faucet devices is probably due to improper filter depth.

Physical and chemical characteristics of the water will also affect performance. The acidity and temperature can be important. Greater acidity and lower water temperatures tend to improve the performance of activated charcoal filters. Activated charcoal filters have a limited lifetime. Eventually, the surface of the activated charcoal will be saturated with adsorbed pollutants and no further purification will occur. This is called breakthrough; the pollutants have broken through the filter to emerge in the treated water. When this occurs, it is possible that the contaminant concentrations in the treated water will be even higher than those in the untreated water. At this time, the cartridge needs to be replaced. Knowing when breakthrough will occur and thus when to replace the cartridge is a major problem with activated charcoal treatment.

Some cartridges are sold with predictions about their longevity. These are generally only crude estimates since they do not take into consideration factors that are characteristic to a specific water source, such as pollutant concentration. The retailer you purchase the treatment device from can make better estimates of the filter’s useful lifetime based on water usage (flow rate) and pollutant concentrations shown in the chemical analysis. Hence, to get the most accurate estimates, you should learn what these amounts are before purchasing the system. Note that if pollutant concentrations increase over time and testing is not performed to reveal this change, such estimates may turn out to be not very practical or useful.

Unfortunately, activated charcoal filters can be excellent places for bacteria to grow. Conditions for bacterial growth are best when the filter is saturated with organic contaminants, which supply the food source for the bacteria, and when the filter has not been used for a long period of time. It is still unclear whether the bacteria growing on the charcoal poses a health threat. Some manufacturers have placed silver in the activated charcoal in order to prevent the growth of bacteria. The effectiveness of this procedure has not been independently verified. In addition, silver may contaminate the drinking water.

The above considerations have led public health officials to consider activated charcoal home treatment a temporary solution to be used only until the source of contamination can be eliminated and the water supply is safe. Even with proper installation, maintenance and operation, malfunction of home water treatment systems can occur.

Activated Charcoal Filter Guidelines

Make sure the filter contains activated charcoal. Know the quantity of activated charcoal in the filter since this will determine the amount and rate of pollutant removal. Use pre-filter to add life to activated charcoal filters. Replace pre-filters and activated charcoal filters regularly. Determine appropriate intervals for replacement of activated charcoal filters based on contaminant concentration, water characteristics, water flow rate, depth of filter, type and amount of activated charcoal and prefilter. Retailers can help in this analysis.

It is always important for students, parents and teachers to know a good source for science related equipment and supplies they need for their science activities. Please note that many online stores for science supplies are managed by MiniScience.

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• Science Fair Project Ideas for Kids, Middle & High School Students ⋅

How to Make a Water Filter as a Science Experiment

How to Make an Ecosystem for Kids With Pop Bottles

A water filter science experiment makes a fun and educational rainy-day activity for kids. This filter, made mostly from inexpensive household items, will teach kids about the processes water purification plants use. Putting the filter together is a simple process, easily done on a tabletop in an hour or less.

Cut the soda bottle in half, and remove the top half. Put three layers of cheese cloth over the narrow mouth of the bottle and use rubber bands to hold them in place.

Put the top half upside down into the bottom half so the top half makes a funnel, and the bottom becomes a collector.

Add layers of sand, gravel and charcoal into the top half of the bottle. If you’re working with several groups of children, have them try the layers in a different order and see which arrangement works best. For example, one group adds sand, then activated carbon, then gravel. The sand is at the bottom, and the gravel is on top.

Get some dirty water. If you do not have dirty water you can make some water dirty by using cooking oil, dirt, bits of food, etc.

Pour dirty water into the top half of the bottle. It should run through the sand and gravel, out the cheese cloth and come out clearer in the bottom half of the bottle.

Things You'll Need

• Make sure that an adult cuts the bottle in half. This water filter is just an experiment and should not be used for drinking water.

Avoid using charcoal briquets, as these can contain chemicals you don't want in your water. Use the activated carbon for water purifiers instead.

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• Utah State University: Homemade Water Purifier

About the Author

Cathy Rigden has been writing professionally since 2009. She holds a Bachelors of Arts in early childhood education from Southern Nazarene University and a Master of Arts in teaching from Biola University.

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Create a water filter

Follow FizzicsEd 150 Science Experiments:

You will need:

• Three plastic cups
• Two water bottles (to run two different versions
• A rubber band
• Old stocking material (or kitchen cleaning wipe)
• Sand and gravel with materials of different sizes
• Water and dirt
• Optional cardboard cutter (adult use only)

• Instruction

Make a  cup of dirty water and set it to one side.

Cut each water bottle in half. You can either use the cardboard cutter to make a small cut or alternatively pinch the plastic bottle and then use the scissors to cut the bottle.

Using the rubber band, tie a piece of cut stocking or kitchen wipe onto the opening of the water bottles. Make this fairly strong as it will need to hold the weight of the sand and gravel.

In one water bottle add sand first and then gravel, in the other bottle put the gravel in first and then the sand. The idea is to see if the order of filtering materials makes a difference to how well the water is filtered… all about variable testing!

Balance each of the two bottles upside-down in the remaining cups. Pour the dirty water into each water bottle and see how well the dirty water gets filtered!

You could test how well you’ve filtered water using a secchi disc

Also, try measuring the pH before and after the water filter experiment… did it make any difference?

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Why Does This Happen?

You have created a simple water filter! The sand and gravel particles act as a sieve, trapping larger material from filtering down with the water as it travels downwards. Filtering such as this occurs in the natural environment as well. There are many communities that rely on underground aquifers which have accumulated over millions of years as water has filtered through the soil to the bedrock.

A classic example of an underground aquifer is Australia’s Great Artesian Basin which covers much of Queensland and South Australia with extensions into the Northern Territory and NSW.

You can create a simple model of soil horizons that produce these natural water filters by alternating different sands and gravel in a clear container.

Variables to test

More on variables here

• Try different size sieve meshes by changing the dishcloth type
• What happens if you change the size of the sand and gravel grains?

Learn more!

From surface tension to the water cycle , we’ve got you covered for your next water unit! Get in touch with FizzicsEd to find out how we can work with your class.

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Homemade Water Filter Science Project

Katelyn is a freelance writer and travel blogger who loves writing about travel, health, finance, and science topics. She holds a bachelor's and master's degree in science fields.

Learn about our Editorial Policy .

Seventy percent of the Earth is covered with water. However, only about three percent that can be used for drinking water. While many people in the United States have clean, drinkable water from their kitchen sink, most of the people around the world do not have access to clean water and must boil or filter their water. You can teach your students how to water filters work with this easy project.

Homemade Simple Water Filter

You can easily make a water filter with children using recycled materials found at home. This project is best for children in grades three through six, but it will work for all ages. Construction of the homemade water filter will take about an hour to build. Testing of the water filter can take anywhere from an hour to several hours depending on how fast the water drips. By using natural materials that mimic the water cycle of the Earth, children can learn how the process of infiltration works and create a water filter that works.

• 10 Fun & Easy Ways to Get Your Kids to Drink More Water
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• Plastic soda or juice bottle
• Vase or tall drinking glass
• Gravel or small stones
• Activated Charcoal
• Cotton balls, small cloth or coffee filter
• Gardening dirt
• Scissors or knife

Instructions

• Cut off the bottom of an old plastic soda or juice bottle using scissors or a knife.
• Place the bottle upside down into the vase or tall drinking glass.
• Place cotton balls, cloth, or a coffee filter inside the bottle as the first layer. The first layer should be about one to two inches thick.
• Add an inch of activated charcoal as the second layer on top of the cotton layer.
• Over the charcoal, add about two inches of gravel or small stones as the third layer.
• Add about three to four inches of clean sand on top of the gravel.
• Add gravel to the bottle as the final layer. Leave about a half inch of space from the top of the upside down bottle.
• Add dirt to a glass of water to create muddy water. Alternatively, get creative and add other things like glitter, beads, cooking oil or other materials to make dirty water.
• Pour the glass of muddy water on top of the homemade water filter and watch the water drip clean into the glass below.

How to Test the Water

For this experiment, it is best to test the water before and after the filtration.

• To start, ask the child to make a hypothesis or prediction about the experiment.
• Pour two glasses of water from the kitchen faucet. The first glass will serve as the control. The second glass will be "dirty."
• Dirty the "dirty" water with materials found around the house. The "dirty" water can contain things like dirt, potting soil, glitter, dish detergent, kitchen oils, among other materials found around the house.
• Have the children test the two glasses of water with a home drinking water test kit, like the First Alert Drinking Water Test Kit .

Pour each glass of water through the homemade water filter. Collect the filtered water in a glass. Test both water samples after filtration using the same home drinking water test kit. Compare all the water samples. Did the homemade water filter clean the "dirty" water sample? Is the filtered "dirty" water now the same as the control?

Testing Variables

Many of the materials used to make a homemade water filter can be found around the house and recycled for the purpose of this project. A small washcloth, chamois cloth or coffee filter can be used instead of cotton balls. If gravel is not available, small pebbles or stones can be used. If a plastic soda bottle cannot be recycled, a large funnel can also be used instead.

As part of the experiment, children can test different materials to determine which materials produce the cleanest water. Instead of using sand and gravel, children could try rice and sponges. Kids can build several water filters using different materials to determine which materials filter "dirty" water into clean water.

How the Filter Works

Each layer of the homemade water filter has a purpose. Gravel or small stones are used to filter out large sediments, like leaves or insects, whereas sand is used to remove fine impurities. Finally, the activated charcoal removes contaminants and impurities through chemical absorption.

Learn About the Water Cycle

A homemade water filter is a simple activity that children will love. Not only does the project help children learn about the water cycle, but it's a hands-on experiment using common materials found around the house or outside that will fascinate them. The Earth naturally filters water as it is absorbed into aquifers in the ground. The natural soil of the ground filters leaves, insects, and other debris out of the water as part of the infiltration process of the water cycle. Unfortunately, due to pollution such as lawn care products, household chemicals, and fertilizers, ground water can become contaminated and unsafe to drink.

FREE K-12 standards-aligned STEM

curriculum for educators everywhere!

Find more at TeachEngineering.org .

• TeachEngineering
• Water Filtration Project: Make Your Own Water Filters

Hands-on Activity Water Filtration Project: Make Your Own Water Filters

Grade Level: 4 (3-5)

Time Required: 1 hour

This activity also requires some non-expendable items; see the Materials List for details.

Group Size: 3

Activity Dependency: None

Subject Areas: Number and Operations, Science and Technology

NGSS Performance Expectations:

TE Newsletter

Engineering connection, learning objectives, materials list, worksheets and attachments, more curriculum like this, introduction/motivation, investigating questions, user comments & tips.

Clean water is not available in all parts of the world. Many people live with polluted water that is unhealthy to drink and bathe in. Civil, environmental , materials and mechanical engineers all contribute to developing technologies and systems to purify unclean water. Purifying water can be done easily if it is a small amount that is fairly clean, but larger amounts that are very polluted are much more complicated. Typical steps for full water treatment include aeration, coagulation, sedimentation, filtration and disinfection.

After this activity, students should be able to:

• Understand how filtration works.
• Create creative design methods.
• Problem solve given a design challenge.
• Apply mathematics (multiplication) reinforcement.
• Engage in teamwork to solve a challenge.

Educational Standards Each TeachEngineering lesson or activity is correlated to one or more K-12 science, technology, engineering or math (STEM) educational standards. All 100,000+ K-12 STEM standards covered in TeachEngineering are collected, maintained and packaged by the Achievement Standards Network (ASN) , a project of D2L (www.achievementstandards.org). In the ASN, standards are hierarchically structured: first by source; e.g. , by state; within source by type; e.g. , science or mathematics; within type by subtype, then by grade, etc .

Ngss: next generation science standards - science.

Common Core State Standards - Math

View aligned curriculum

Do you agree with this alignment? Thanks for your feedback!

International Technology and Engineering Educators Association - Technology

State standards, massachusetts - math, massachusetts - science.

• 1 liter of water prepared in advance with soil and sand in it until it is thin but relatively opaque
• 3 test tubes prepared with the water standards "A," "B" and "C" (C is filtered through some grass, B is filtered through a coffee filter, and A is filtered through 2 coffee filters with a paper towel in the middle)
• cotton balls
• gauze squares
• tulle/netting
• paper towels
• coffee filters
• gravel (aquarium gravel works great)
• 3 test tubes per student
• test tube racks
• graduated cylinders
• Design Components Worksheet

One of our most valuable and often overlooked resources is water. We can survive for a few weeks without food, but only a few days without water. Having clean water to drink is a luxury. The water that eventually comes out of our faucets sometimes does not start off being safe to drink. In most cases, it has gone through a water treatment plant designed by engineers prior to reaching our faucets.

This is a great activity for students to experience some "real-life" engineering.

Most any materials in a typical classroom can be adapted as filtration materials.

Water from lakes and rivers often has contaminants that make it unfit for drinking. The water may contain dirt, rocks and other objects that can be easily identified. Water may also contain bacteria and other microscopic organisms that cannot be seen easily. For these reasons, water that is delivered to our homes must go through a water treatment process. This is typically a five-part process that consists of aeration, coagulation, sedimentation, filtration and disinfection. This activity is only concerned with filtration, which removes most but not all of the impurities from the water. Make sure students know that in this activity the filtered water is still unfit to drink.

Recommended Resources:

Information on the water treatment process and drinking water standards: https://www.epa.gov/ground-water-and-drinking-water .

Information on different types of filters and filtration processes: https://www.thoughtco.com/filtration-definition-4144961 .

Before the Activity

• Gather materials and make copies of the Design Components Worksheet .
• Make the liter of dirty water and the "A," "B" and "C" tubes.

With the Students

• Engineering Challenge : Tell the students they have been hired by (your last name) Water Supply Company. With the ongoing drought, not enough water is available for all the things we need to supply – people, animals and plants. Tell them that they will each be given a sample of the dirty water they have remaining, and show them the tubes "A," "B" and "C." A is nearly ready for human use, B is nearly ready for animal use, and C is nearly ready to feed the plants. Remind them that no one must taste anything in the lab. They will be paid for their supply of filtered water: A gets $10 per ml, B gets $5 per ml, and C gets $1 per ml.
• Have students complete the worksheet to make sure they understand the activity purpose, and to help them think about the components of engineering design.
• Put trays of materials in front of the students. Let them decide in teams what materials they would like to use to filter their water. To challenge students, include one of the following constraints:
• Limit the amount of materials allowed for the design.
• Assign a price per unit of material and give students a budget to work within.
• Have students draw schematics of the layers. Once completed, give each team 25 ml of the dirty water to begin to filter in their test tubes.
• Once filtering is complete, have them bring the test tubes to you for observation. Decide if the water is A, B or C grade and help them measure their sample in a graduated cylinder. They must return to their desks and do the math to come up with their $ value. Have students put their $ values on the board.

Activity Embedded Assessment

Have students complete the Design Components Worksheet to assess their understanding of the activity and to encourage them to consider the design components involved in design a water filtration system. Sample answers are provided on the Design Components Worksheet Answer Key .

Post-Activity Assessment

Use the attached Rubric for Performance Assessment to evaluate students' design projects using criteria for the final filtering system and teamwork effort.

• What was the best filtering agent and why?
• What are other ways we purify our water?
• Design a package for your "clean" water.

Safety Issues

Make sure students know that in this activity the filtered water is still unfit to drink.

Students learn about water quality testing and basic water treatment processes and technology options. Biological, physical and chemical treatment processes are addressed, as well as physical and biological water quality testing, including testing for bacteria such as E. coli.

Students learn about the various methods developed by environmental engineers for treating drinking water in the United States.

Contributors

Supporting program.

Last modified: October 24, 2019

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How to Make a DIY Water Filtration System Using Sand or Gravel

For our purposes of diying a water filter system, you'll want to use more natural materials like sand and gravel or small rocks..

Water is something most people take for granted because it’s so easy to turn on the faucet and fill a glass with the cool, pure liquid. But, there are times when access to clean drinking water is not so straightforward.

In those cases, it’s handy to know how to make a water filtration system.

When Might You Need or Want a DIY Water Filtration System?

If you’re trying to survive in dire circumstances and the only nearby source of water is a stream or lake, a DIY water filtration system could help you stay hydrated without also consuming dirt.

Many people in developing countries learn to build water filtration systems so they can avoid illnesses, although they use a more detailed method than the one covered below. It removes contaminants as well as filtering out debris. The one you’ll learn about below only does the latter.

You may also want to create a water filtration system at home as a project to educate your curious kids and go into depth about how important it is to drink clean water and how even if a water source appears clean, looks can be deceiving.

The kind of water filtration system explained below doesn’t require a substantial investment. It uses easily well-known materials, like sand and gravel, to filter out things like mud. Charcoal is perhaps the most crucial ingredient for removing any stuff you don’t want to drink, and most traditional water filters contain it. Let’s get started.

1. Cut the Bottom off a Small Plastic Water Bottle

Begin by finding a plastic water bottle, like a Gatorade container, and cut about a half-inch off, working from the bottom of the bottle up.

As a point of reference, the neck of the bottle will be the bottom of the filter, and the part with the opening you created is the top. Keep the plastic cap on the top end of the bottle. Some methods of making this kind of filtration system advise making a hole in the bottle’s cap with a screwdriver.

2. Insert a Cloth Filter

The next step is to stuff a soft filter into the bottle and push it toward the neck. A bandana works well as a filter, and it’s a readily found item. Alternatively, you could use several cotton balls or a coffee filter.

3. Rinse the Filtering Materials

Before you start adding substances to the bottle that act as filters, rinse all of them thoroughly. Doing this should mean the first portion of water passing through should have less debris than if you used unwashed materials.

Many traditional water filtering methods you see today rely on special kinds of membranes made from a polymer called PTFE — or, its full name, polytetrafluoroethylene. However, for our purposes of DIYing a water filter system, you’ll want to use more natural materials like sand and gravel or small rocks. Hence, rinsing off these filtering materials is an important step in creating a clean water filter.

3. Prepare the Charcoal

Get another piece of cloth and use it to spread out your charcoal. If you have charcoal from a grill or fire pit, that’s a good source.

Make sure to break the charcoal into small chunks, using an object like a large rock to crush it if needed. After working with the charcoal to make it the desired size, wrap the cloth around the substance tightly. Finally, slide it into the bottle against the first piece of cloth.

4. Add Playground Sand

From here, creating your DIY water filtration system means adding more gravel to assist with the purification. You’ll start with the finest material and add layers of progressively coarser stuff. Put playground sand directly on top of the charcoal layer. You don’t need to wrap it in a cloth before pouring in the bottle, but add enough to fully cover the cloth.

5. Put in Paver Sand

Paver sand — also called polymeric sand — comprises the next layer. When running it through your hands, you’ll notice it’s more likely to have small stones in it that the playground sand didn’t have.

6. Add the Gravel or Small Rocks

The final two layers of this filter are fine gravel and coarser gravel. Depending on your area, you may find it in nature. Due to the modest diameter of the plastic bottle, you shouldn’t need more than a couple of handfuls, equaling an inch or two of coverage.

7. Secure the Contents

You’ve now added everything to the filtration system, and it’s time to make sure all your hard work doesn’t go to waste. Get another piece of cloth and stretch it tightly over the bottom of the bottle. Keep the soft material in place with a rubber band or a cable tie.

8. Pass the Water Through the Filter

You’re finally ready to start seeing the fruits of your labor. Hold your filter over an empty cup and take off the cap. Then, pour water on top of and through the filter and wait for it to come through the neck of the bottle and into the cup. This type of portable water filter is good to take when you go backpacking.

It’s Easy to Filter Your Water at Home

These steps demonstrate it’s not as challenging as some people think to filter water at home or wherever they are. Keep in mind, though, that you still need to use water purification tablets to make the water potable.

Kayla Matthews writes and blogs about healthy living, sustainable consumption, eco-friendly practices and green energy. In the past, her work has also been featured on GRIT, Mother Earth Living , Blue And Green Tomorrow, Dwell and Houzz. To read more from Kayla, follow her productivity and lifestyle blog: Productivity Theory.

All MOTHER EARTH NEWS community bloggers have agreed to follow our Blogging Guidelines, and they are responsible for the accuracy of their posts. To learn more about the author of this post, click on their byline link at the top of the page.

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• For Teachers

• Everyday Activities
• Experiments

Water Filter

Can you make muddy water crystal clear?

Make your own water filter!

You'll be able to remove dirt, heavy metals and chemicals from filthy water!

Watch the video on YouTube: https://youtu.be/fHbeJaScUnA

You Will Need

2 liters of stream or river water (or mix a handful of dirt into 2 liters of water)

2 empty clear 1-liter plastic soda bottles

30 cotton balls

A thumb tack

A stick or skewer

Optional: 2 cloth circles, about 6 inches in diameter, or round coffee filters

2 cups of cleaned activated carbon (charcoal) (this can be found in most pharmacies in the vitamin section)

2 cups of sand

1 cup of fired clay pieces (we crushed up inexpensive terracotta flower pots)

Several empty 12 oz cups to collect your filtered water (The bottle should be able to sit snugly in the top of the cups)

Materials & Directions PDF

• Example: Does changing the arrangement of the layers affect how quickly the water is filtered?
• 1 hole per “bump” on the bottom of the bottle works well.

• Layer 10-15 cotton balls in the bottom of each bottle. Pull them slightly apart, then use the skewer or stick to smush them down into all of the bumps in the bottom of the bottle. The cotton needs to cover the entire bottom of the bottle to keep the sand from coming out.
• Getting the cloth or filter in the bottle and then over the cotton can be tricky. You could ask an adult to cut the spout off your bottle so you have a larger opening to work with.
• A sand layer of about 7cm or 2 ½ inches deep is recommended.
• Experiment by adding additional layers. You could make one filter using the charcoal, make another one using the fired clay, or make one filter that uses both, or make one with just sand - experiment!
• Place a cup under your filter to catch the filtered water.
• Place the small end of the funnel in the top of the bottle and pour about 1.5 cups of the dirty water into the top of your filter. Wait several minutes for the water to filter through. The water should drip SLOWLY out of the bottom of the filter.
• See how many times you need to pour the water through your filter(s) until it becomes clear. Make a chart to track which filter works best.
• DO NOT DRINK IT! (In many cases, boiling the water for at least 1 minute would make it safe to drink, but we DO NOT recommend drinking the water from this experiment, just to be safe!)

Discovery Questions

Beginning the experiment, during the experiment, after the experiment, how it works.

The different layers of the filter help to pull the dirty particles out of the water.

• The cotton ball layer helps to keep the other layers of your filter from falling out into your water.
• The sand layer acts as a coarse filter for large muddy particles and to keep the activated charcoal or clay particles from getting into the cleaned water.
• The fired ceramic clay attracts metallic ions and is good for attracting and filtering out metallic particles.
• The activated charcoal layer is amazing at trapping the impurities in its network of holes and tunnels.

Activated charcoal is carbon that has been treated with oxygen at very high temperatures. The oxygen eats away at the carbon and makes all kinds of tunnels and pores. Just three grams of activated charcoal can have as much surface area as a football field! As water passes through this porous charcoal, the little particles and impurities get trapped inside the charcoal. “Activated” means it has a slightly positive charge and works like a magnet on negatively charged impurities that are attracted and bind to the outside of the charcoal.

After running your dirty water through the filter a number of times, it will appear to be nice and clean. But even though it looks completely clear, it MUST be thoroughly sterilized before it could be used for drinking. Boiling water is a common technique for removing pathogens, but avoid doing so unless absolutely necessary. (Again, we DO NOT recommend drinking the water from this experiment, just to be safe!)

Did you know that 75% of the earth’s surface is covered by water? Most of it is salt water and can’t be used for drinking. In fact, less than 1% of the earth’s water can be used by people!

As you saw with this experiment, filtering dirty water to make it clean enough to drink takes time and effort. It is very important to save the water we use every day and not waste it. What are some ways you can conserve water every day?

For more information, visit:

https://www.epa.gov/watersense/how-we-use-water

Science Fun

Make A Water Filter Science Experiment

In this fun and easy water science experiment, we’re going to make a water filter. 

• Two baking pans
• Empty two liter bottle
• Medium sized flower pot
• Coffee filter

Instructions:

• Put the coffee filter into the flower pot.
• Put about two inches of pebbles into the bottom of the flower pot.
• Pour sand into the pot until it is about three quarters full.
• Use your funnel to add about a cup of dirt to your two liter soda bottle.
• Fill the bottle nearly full with water.
• Put on the cap and shake the bottle to mix the soil and water.
• Pour some of the muddy water into one of the pans.
• Now set the flower pot in the other pan.
• Slowly pour the muddy water into the flower pot and observe the water that comes out into pan.
• The water will not be very clear at first. Keep working the water through your filter system and compare it to your control sample of muddy water.

EXPLORE AWESOME SCIENCE EXPERIMENT VIDEOS!

How it Works:

The pebbles and sand act as a natural filter and will help purify the water. 

Make This A Science Project:

Try adding food coloring to the water. Try different amounts of pebbles and sand. 

EXPLORE TONS OF FUN AND EASY SCIENCE EXPERIMENTS!

SUBSCRIBE AND NEVER MISS A NEW SCIENCE FUN VIDEO!

How to Make a Homemade Water Filter - Science Experiment

Introduction: How to Make a Homemade Water Filter - Science Experiment

Today we are going to be learning about how wastewater is cleaned locally and we will be making a homemade experiment to help you understand the system better.

Step 1: How to Make a Homemade Water Filter - Local Water Issues

One problem locally is wastewater, now we all know how crucial water is in our everyday lives and to Earth but today I will be showing you one way to separate the dirty water which portrays all the diseases and other hazardous waste using a DIY filter.

First we need to know what our community is doing as a whole to understand this experiment so let's watch the quick video above to understand.

What is wastewater made up of?

Municipal Wastewater can contain sanitary sewage, solids, disease-causing organisms, decaying organic wastes, nutrients and other household and industrial wastes.

Some ways that Peel maintains the Wastewater Collection System includes:

• Sewage pumping stations
• The York-Peel Odour and Corrosion Control Facility
• Over 3,500 km of sanitary sewer main
• Over 52,000 maintenance holes
• Sanitary sewer laterals to the private property line for all connected properties

Step 2: Materials Needed & a Step by Step Tutorial Video

- 1 or 2 litre bottle (I will be using a 2 litre bottle for this experiment)

- Gravel/Stones

- Dirty water

Step 3: Process of Making the Filter

Cut the bottle in half then place cotton in the upper part of the bottle near it's rim.

Flip the top part of the bottle upside-down then place it in the lower half of the bottle.

Pour sand over the cotton until the sand overpowers the cotton.

Crush 2 blocks of charcoal into finely ground pieces with a hammer then add the multiple pieces of charcoal into the upper half of the bottle.

Add a handful of both gravel and pebbles.

Step 8: Final Step

Finally, grab your 'dirty water' and begin pouring it from the top of the filter and see cleaner water come out the other end.

The combination of gravel, pebbles, sand and charcoal all help in purifying the water.

• Gravel and pebbles filter out larger sediments
• Sand helps to filter out fine impurities
• Charcoal removes contaminants and impurities by the process of adsorption

Note: Water from the filter is still not safe enough for consumption, it is advised that you boil the water before drinking.

If you want to contribute to the Wastewater Collection System or you need help with your water or sewer, contact them at 905-791-7800 or toll-free at 905-584-2216 (Caledon or other long-distance areas).

For any questions: email Public Works .