purifying water 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!

Photographs by Mark Thiessen / NG Staff: Adapted from the Nat Geo Kids book How Things Work , by T.J. Resler

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From kitchen to classroom

• 1 Introduction
• 2 Separation techniques
• 3 Red cabbage rainbows
• 4 Making bath bombs
• 5 How to make butter
• 6 Tricking taste buds with toothpaste
• 7 Kitchen roll chromatography
• 8 Investigating surface tension with milk
• 9 Chalky spinach
• 10 How to purify water

How to purify water

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Water, water everywhere, let’s purify it and have a drink! Explore how to purify your own water with this experiment

In this video,  education coordinator  Catherine demonstrates how the water cycle can be used on a smaller scale to purify water. This simple activity can be set for learners to try at home with a responsible adult or used as a classroom experiment.

Equipment list

• One big container, and a small container that fits inside the large one
• Contaminant like food colouring and salt
• Something heavy like a pebble, or a ball of blu-tac

Health and safety

• If trying the water afterwards, make sure all your equipment is clean beforehand.
• If using any non-food contaminants, do not drink the water at the end of the experiment.

Activity instructions

• Make your contaminated water by mixing in a contaminant like salt or food colouring into a small amount of water. Please note that the more water you use, the longer the experiment will take.
• Assemble the experiment with the smaller container inside the larger one. Pour the contaminated water into the larger outer container.
• Cover the whole experiment with cling film. If necessary, secure with tape or an elastic band.
• Place the weight (a pebble or ball of blu-tac) in the centre of the cling film, so that it creates a low point directly above the smaller container in the middle.
• Place the experiment in a sunny spot, and wait – you can observe the changes over time.

Explanation

The water cycle, consisting of evaporation, condensation and precipitation, is an important topic for learners, and this demonstration gives a great visual aid to understand what goes on in our atmosphere. It’s also a good way to show reversible changes and how the dissolved contaminant can be separated from the mixture, and how a liquid can change state into a gas and then back to a liquid.

If you’d like to contextualise this experiment, here are some ideas:

• In space, astronauts need to clean their limited supply of water.
• You need to purify sea water after finding yourself stranded on a desert island.
• The school has asked about the differences between diet fizzy drinks and full-fat, so you could see what happens when you try to evaporate the liquids and what’s left behind.

Also check out

• For this and other space-related experiments with water, check out the Life of Water  experiment pack.
• Other separating mixtures experiments, like ‘heavy sugar’ to investigate the amount of sugar in a soft drink.
• More simple experiments using everyday equipment which your learners can try at home or you can bring to the classroom on our  YouTube playlist .
• Read the CLEAPSS guidance on practical activities for pupils at home during extended periods of school closure,  GL339 .
• Read the SSERC guidance for  primary home learning .

How to purify water teacher notes

Introduction

Separation techniques

Red cabbage rainbows

Making bath bombs

How to make butter

Tricking taste buds with toothpaste

Kitchen roll chromatography

Investigating surface tension with milk

Chalky spinach

• Practical experiments
• Practical skills and safety
• Compounds and mixtures

Specification

• Mixtures can be separated by physical processes such as filtration, crystallisation, simple distillation, fractional distillation and chromatography. These physical processes do not involve chemical reactions and no new substances are made.
• Describe, explain and exemplify the processes of simple distillation.
• 2.5 Explain the difference between the use of ‘pure’ in chemistry compared with its everyday use and the differences in chemistry between a pure substance and a mixture
• C1.4.1 describe the principal methods for increasing the availability of potable water, in terms of the separation techniques used, including the ease of treating waste, ground and salt water including filtration and membrane filtration; aeration, use of…
• C6.2g describe the principal methods for increasing the availability of potable water in terms of the separation techniques used
• C6.3g describe the principal methods for increasing the availability of potable water in terms of the separation techniques used
• Water treatment - sedimentation, flocculation, filtration, chlorination, fluoridation and pH adjustment.
• Awareness of the contributions of chemistry to society, e.g. provision of pure water, fuels, metals, medicines, detergents, enzymes, dyes, paints, semiconductors, liquid crystals and alternative materials, such as plastics, and synthetic fibres; increasi…
• 2. Research different energy sources; formulate and communicate an informed view of ways that current and future energy needs on Earth can be met.
• 1. Describe the cycling of matter, including that of carbon and water, associating it with biological and atmospheric phenomena.
• 2. Develop and use models to describe the nature of matter; demonstrate how they provide a simple way to to account for the conservation of mass, changes of state, physical change, chemical change, mixtures, and their separation.

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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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37 Water Science Experiments: Fun & Easy

We’ve curated a diverse selection of water related science experiments suitable for all ages, covering topics such as density, surface tension, water purification, and much more.

These hands-on, educational activities will not only deepen your understanding of water’s remarkable properties but also ignite a passion for scientific inquiry.

So, grab your lab coat and let’s dive into the fascinating world of water-based science experiments!

Water Science Experiments

1. walking water science experiment.

This experiment is a simple yet fascinating science experiment that involves observing the capillary action of water. Children can learn a lot from this experiment about the characteristics of water and the capillary action phenomenon. It is also a great approach to promote scientific curiosity and enthusiasm.

Learn more: Walking Water Science Experiment

2. Water Filtration Experiment

A water filtering experiment explains how to purify contaminated water using economical supplies. The experiment’s goal is to educate people about the procedure of water filtration, which is crucial in clearing water of impurities and contaminants so that it is safe to drink.

Learn more: Water Filtration Experiment

3. Water Cycle in a Bag

The water cycle in a bag experiment became to be an enjoyable and useful instructional exercise that helps students understand this idea. Participants in the experiment can observe the many water cycle processes by building a model of the water cycle within a Ziplock bag.

4. Cloud in a Jar

The rain cloud in a jar experiment is a popular instructional project that explains the water cycle and precipitation creation. This experiment is best done as a water experiment since it includes monitoring and understanding how water changes state from a gas (water vapor) to a liquid (rain) and back to a gas.

Learn more: Cloud in a Jar

5. The Rising Water

The rising water using a candle experiment is a wonderful way to teach both adults and children the fundamentals of physics while also giving them an exciting look at the properties of gases and how they interact with liquids.

6. Leak Proof Bag Science Experiment

In the experiment, a plastic bag will be filled with water, and after that, pencils will be inserted through the bag without causing it to leak.

The experiments explain how the plastic bag’s polymer chains stretch and form a barrier that keeps water from dripping through the holes the pencils have produced.

Learn more: Leak Proof Bag Science Experiment

7. Keep Paper Dry Under Water Science Experiment

The experiment is an enjoyable way for demonstrating air pressure and surface tension for both adults and children. It’s an entertaining and engaging technique to increase scientific curiosity and learn about scientific fundamentals.

Learn more: Keep Paper Dry Under Water Science Experiment

8. Frozen Water Science Experiment

The Frozen Water Science Experiment is a fun and engaging project that teaches about the qualities of water and how it behaves when frozen.

You can gain a better knowledge of the science behind the freezing process and investigate how different variables can affect the outcome by carrying out this experiment.

9. Make Ice Stalagmites

10. Bending of Light

A fascinating scientific activity that explores visual principles and how light behaves in different surfaces is the “bending of light” water experiment. This experiment has applications in physics, engineering, and technology in addition to being a fun and interesting method to learn about the characteristics of light.

11. Salt on a Stick

This experiment is an excellent way to catch interest, engage in practical learning, and gain a deeper understanding of the characteristics of water and how they relate to other substances. So the “Salt on Stick” water experiment is definitely worth trying if you’re looking for a fun and educational activity to try!

Learn More: Water Cycle Experiment Salt and Stick

12. Separating Mixture by Evaporation

This method has practical applications in fields like water processing and is employed in a wide range of scientific disciplines, from chemistry to environmental science.

You will better understand the principles determining the behavior of mixtures and the scientific procedures used to separate them by performing this experiment at home.

13. Dancing Spaghetti

Have you ever heard of the dancing spaghetti experiment? It’s a fascinating science experiment that combines simple materials to create a mesmerizing visual display.

The dancing spaghetti experiment is not only entertaining, but it also helps you understand the scientific concepts of chemical reactions, gas production, and acidity levels.

14. Magic Color Changing Potion

The magic color-changing potion experiment with water, vinegar, and baking soda must be tried since it’s an easy home-based scientific experiment that’s entertaining and educational.

This experiment is an excellent way to teach kids about chemical reactions and the characteristics of acids and bases while providing them an interesting and satisfying activity.

15. Traveling Water Experiment

In this experiment, you will use simple objects like straws or strings to make a path for water to pass between two or more containers.

Learn more: Rookie Parenting

16. Dry Erase and Water “Floating Ink” Experiment

The dry-erase and water “floating ink” experiment offers an interesting look at the characteristics of liquids and the laws of buoyancy while also being a great method to educate kids and adults to the fundamentals of science.

Learn more: Dry Erase and Water Floating Ink Experiment

17. Underwater Candle

In this experiment, we will investigate a connection between fire and water and learn about the remarkable factors of an underwater candle.

18. Static Electricity and Water

19. Tornado in a Glass

This captivating experiment will demonstrate how the forces of air and water can combine to create a miniature vortex, resembling a tornado.

Learn more: Tornado in a Glass

20. Make Underwater Magic Sand

Be ready to build a captivating underwater world with the magic sand experiment. This experiment will examine the fascinating characteristics of hydrophobic sand, sometimes referred to as magic sand.

21. Candy Science Experiment

Get ready to taste the rainbow and learn about the science behind it with the Skittles and water experiment! In this fun and colorful experiment, we will explore the concept of solubility and observe how it affects the diffusion of color.

Density Experiments

Density experiments are a useful and instructive approach to learn about the characteristics of matter and the fundamentals of science, and they can serve as a starting point for further exploration into the fascinating world of science.

Density experiments may be carried out with simple materials that can be found in most homes.

This experiment can be a great hands-on learning experience for kids and science lovers of all ages.

22. Super Cool Lava Lamp Experiment

The awesome lava lamp experiment is an entertaining and educational activity that illustrates the concepts of density and chemical reactions. With the help of common household items, this experiment involves making a handmade lava lamp.

Learn more: Lava Lamp Science Experiment

23. Denser Than you Think

Welcome to the fascinating world of density science! The amount of matter in a particular space or volume is known as density, and it is a fundamental concept in science that can be seen everywhere around us.

Understanding density can help us figure out why some objects float while others sink in water, or why certain compounds do not mix.

24. Egg Salt and Water

Learn about the characteristics of water, including its density and buoyancy, and how the addition of salt affects these characteristics through performing this experiment.

25. Hot Water and Cold-Water Density

In this experiment, hot and cold water are put into a container to see how they react to one other’s temperatures and how they interact.

Sound and Water Experiments

Have you ever wondered how sound travels through different mediums? Take a look at these interesting sound and water experiments and learn how sounds and water can affect each other.

26. Home Made Water Xylophone

You can do this simple scientific experiment at home using a few inexpensive ingredients to create a handmade water xylophone.

The experiment demonstrates the science of sound and vibration and demonstrates how changing water concentrations can result in a range of tones and pitches.

Learn more: Home Made Water Xylophone

27. Create Water Forms Using Sound!

A remarkable experiment that exhibits the ability of sound waves to influence and impact the physical world around us is the creation of water formations using sound.

In this experiment, sound waves are used to generate patterns and shapes, resulting in amazing, intricate designs that are fascinating to observe.

28. Sound Makes Water Come Alive 

These experiments consist of using sound waves to create water vibrations, which can result in a variety of dynamic and captivating phenomena.

29. Water Whistle

The water whistle experiment includes blowing air through a straw that is submerged in water to produce a whistle.

This experiment is an excellent way to learn about the characteristics of sound waves and how water can affect them.

Water Surface Tension Experiments

You can observe the effects of surface tension on the behavior of liquids by conducting a surface tension experiment.

By trying these experiments, you can gain a better understanding of the properties of liquids and their behavior and how surface tension affects their behavior.

30. Floating Paperclip

In this experiment, you will put a paper clip on the top of the water and observe it float because of the water’s surface tension.

31. Water Glass Surface Tension

Have you ever noticed how, on some surfaces, water drops may form perfect spheres? The surface tension, which is a characteristic of water and the cohesive force that holds a liquid’s molecules together at its surface, is to blame for this.

32. Camphor Powered Boat

The camphor-powered boat experiment is a fun and fascinating way to explore the principles of chemistry, physics, and fluid mechanics. In this experiment, a miniature boat is used to travel across the water’s surface using camphor tablets.

33. Pepper and Soap Experiment

The pepper in a cloud experiment is a simple and interesting activity that explains the concept of surface tension. This experiment includes adding pepper to a bowl of water and then pouring soap to the mixture, causing the pepper to move away from the soap.

Learn more: Pepper and Soap Experiment

Boiling Water Experiments

Experiments with boiling water are an engaging and informative way to learn about physics, chemistry, and water’s characteristics.

These investigations, which include examining how water behaves when it changes temperature and pressure, can shed light on a variety of scientific phenomena.

It’s important to take the proper safety measures when performing experiments with hot water. Boiling water can produce steam and hot particles that are dangerous to inhale in and can result in severe burns if it comes into contact with skin.

34. Make It Rain

This experiment can be accomplished using basic supplies that can be found in most homes, make it an excellent opportunity for hands-on learning for both kids and science lovers.

Learn more: Make it Rain

35. Fire Water Balloons

Learning about the fundamentals of thermodynamics, the behavior of gases, and the effects of heat on objects are all made possible by this experiment.

36. Boil Water with Ice

The Boiling Water with Ice experiment is an engaging and beneficial approach to learn about temperature and the behavior of water. It can also serve as an introduction for further discovery into the wonderful world of science.

37. Boil Water in a Paper Cup

The “boil water in a cup” experiment is an easier but powerful approach to illustrate the idea of heat transmission by conduction. This experiment is often used in science classes to teach students about thermal conductivity and the physics of heat transfer.

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