How to Make a Water Filter as a Science Experiment

••• Sciencing

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.

Step 1

••• Sciencing

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.

Step 2

••• Sciencing

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

Step 3

••• Sciencing

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.

Step 4

••• Sciencing

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.

Step 5

••• Sciencing

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

  • Napkins
  • 2 liter soda bottle
  • Gravel (aquarium gravel will work)
  • Sand
  • Activated carbon
  • Dirty water
  • Cheese cloth
  • Rubber bands


  • 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.

Related Articles

How to Make a Water Filter Using Sand & Rocks
How to Make a Volcano for Kids Using Mud
How to Make an Ecosystem for Kids With Pop Bottles
How to Make a Model Heart With Materials From Your...
Citric Acid Experiments
How to Separate Ink From Water
Effects of Lime & Alum on Water Purification
Water Bottle Science Experiments
School Projects on Pollution
School Project: How to Make a Volcano That Blows Ash
Project Ideas for an Egg Drop With Instructions
How to Mix Vinegar & Baking Soda in a Bottle Rocket
How to Convert Gallons to Metric Tons
How to Make Compost for Kids
How to Keep an Egg Soaking in Vinegar for a Science...
How to Make Bromine Water in the Chemistry Lab
How to Make a Volcano
How to Extract Pure Caffeine From Coffee

Dont Go!

We Have More Great Sciencing Articles!