Water Filter

In this activity, you will…

build a water filter!

Supplies Required:

  • Water bottle
  • Sand
  • Cotton balls
  • Gravel (small rocks)
  • Water
  • Dirt
  • Napkin
  • Coffee filter
  • Clear cups

The Challenge:

You went on a camping trip and your car breaks down! So now you’re stranded in the woods with nothing to drink but the water in a nearby pond and the rain that falls from the clouds! We know that drinking water from rain or a pond can make us sick because of the bacteria that might live in the water, but this is a desperate situation. We don’t know how long it will take until help arrives and we don’t have cell phone service.

How can filter and/or purify the water so that we can stay hydrated and not get sick?

Problem and Solutions:

2 + 6 =

Let’s build a model!


  1. On a piece of scrap paper, draw some filter designs that you think could help clean the pond water.
  2. Gather the materials listed above and any additional materials you have at home you think will help your design.
  3. In the clear cups you have been provided, make one or more of the water filter systems you drew. Make sure they flow one way so you can pour dirty water in through one side of your filter and have it come out the other side.
  4. Mix dirt with water in a separate cup to serve as a model for the pond water.
  5. Test your models! Pour water into each filter, re-capturing it on the other end in another clear cup or container. Does the dirty water come out cleaner?

Result, Reflection, and Redesign

8 + 12 =

Think about it and additional resources:

It’s easy to make a water filter at home with lots of materials on hand! If you were to get stuck on the side of the road with only a pond nearby and the things in your car, what might you use? Are there items in nature you can use to make a water filter? What other ways are there to purify water beyond a physical filtration sytem? Finally, what’s in pond water anyways that can make us sick?

In these videos, you’ll learn:

  • how real water filters work
  • what is in pond water and look at it under the microscope
  • how you might make a primitive water filter
  • other ways you can purify water in the wilderness


Share It Out!

  • General Information

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