How to Make a Water Filter for School

Easy water filters

There is nothing like hands-on instruction to make a lesson stick with students. When studying science, specifically environmental science of lab instruction, a great beginning lesson is to build a simple water filter. The materials and methods are simple and straightforward and kids can do most of the work themselves. While the water filtered in this manner should not be used for human consumption, it will be cleaner and will teach students the basics of filtration systems.

Things You'll Need

• 2-liter bottle
• Sand--fine and large grain
• Gravel
• Cotton batting
• Coffee filter

Instructions

1. Remove the bottom 2 inches of a 2-liter soda bottle. Depending on the age of the students, the teacher may want to do this step. Take a pair of scissors and cut around the base of the bottle. This wide mouth opening will become the top of the filter.

2. Insert the base of the filtration system. Unscrew the bottle's cap and tip the bottle upside down so that the wide mouth ins now the top. Insert a layer of cotton batting about 2 inches thick. This will be the last material the water filters through.

3. Add sand and gravel. Alternate layers of sand and gravel in the following order until the bottle is 2/3 full. Fine sand, course sand, small gravel, repeat. Each layer should be approximately 1 inch thick.

4. Lay a coffee filter at the top of the sand gravel layers. This will be the first thing the dirty water passes through.

5. Test the filter. Pour dirty water in slowly and let it run through the layers of coffee filter, sand, gravel and cotton batting.

References

• Homemade Water Filter - Tips and Steps