What You Need:
- 1/2 cup dry soil
- 1/2 teaspoon blue powdered tempera paint
- Funnel
- Wide-mouthed jar (that the funnel can rest in)
- Coffee filter
- Cups or containers
- Water
- Measuring cup
What You Do:
- Mix the dry soil and tempera paint thoroughly. Place the funnel in the jar and place the coffee filter in the funnel. Pour the soil mixture into the funnel.
- Slowly pour 1/2 cup water into the funnel, watching as the water runs out of the funnel into the jar. Notice the color of the water.
- Remove the funnel from the jar and pour the water into a cup or container. Replace the funnel over the jar, with the coffee filter full of sand still in place.
- Repeat steps 2 and 3 with a fresh 1/2 cup of water several times, saving the water in a new cup after each pouring.
What Happened:
When the first half cup of water went through the soil, the water that came out was very dark blue in color. However, each subsequent cup that went through the soil mixture came out lighter and lighter. Eventually, the water traveling through the soil came out clear in the jar. How many half cups of water did it take for the water to run clear?
The tempura paint in this experiment represents the nutrients and dissolved particles found in the soil. Water is a very efficient transporter of particles as evidenced by the color of water as it was poured through the soil. The soil started with a relatively high amount of nutrients and particles in it — the tempura paint. The water flowing through the soil was able to pick up a large proportion of the ‘nutrients’ and carry them with it through the funnel. Each subsequent pouring of water picked up more nutrients. With each pouring, the remaining nutrients became less and less until the water ran clear and there were no more nutrients left to travel with the water.
