Boys holding mud for crafts for kids

Science Experiment: Water Filter Activity

Water Filter Activity

Learn about aquifers and watersheds with this activity! The earth has layers of different rocks and minerals to help filter the water. However, the purification of water depends on many factors such as what is in the soil, if there is any natural filtration, chemical absorption, and more. Using different types of materials will show what helps in the filtration process.

You will need: Plastic soda bottles, Coffee filters, Sand, Gravel, Rocks, Grass, Leaves, Charcoal, Muddy water in a gallon milk jug (can add dish soap for added pollutants) , Rubber bands, Clear plastic cups

  1. Cut off a soda bottle with scissors or a razor knife at the shoulder of the bottle (typically the top of the label). Flip the top half of the bottle into the lower half like a funnel into a cylinder. 
  2. Rubberband the coffee filter to the outside of the bottle where the cap would attach. 
  3. Then have them layer the different materials provided in the bottle. Let each person be creative at this point to show what works and what doesn’t. If you have many people or many groups, perhaps assign certain materials to certain groups to show the difference between the filtration process. 
  4. Pour the muddy water over the layers and see if it comes out clean into the plastic cup. I’ve found that porous rocks/gravel and charcoal help the best!