Grade Level: 7th to 10th; Type: Physical Science
In this experiment we will make sand that resists water.
- What does the fabric protector do to the sand that makes it hydrophobic?
- Why does the oil sink?
- Why does the sand stick so close together?
Most people associate sand with the ocean. What if sand was hydrophobic? In this experiment, we will be making just that.
- Scotchgard or other fabric protector
- Clear glass cup
- Baking pan
- Olive oil
- Food coloring
- Paper towel
- Spread the sand evenly on the baking pan.
- Spray the sand withthe fabric protector.
- Mix it around.
- Repeat steps 2-3 three times.
- Fill the glass cup with water.
- Slowly pour the sand into the water. Observe. (It should clump on top of itself, tightly packed like pasta.)
- Dump all the water out of the glass and pour the sand onto the paper towel. (It should be completely dry, since it is waterproof.)
- Now fill the cup with water again.
- Add a drop of olive oil on the water.
- Add a drop of food coloring right onto the olive oil, not the water.
- Now pour the sand in. What happens to the oil? (The sand pulls the oil down with it. Oil is lighter than water, yet the sand manages to keep it underwater for a while.)
Terms/Concepts: hydrophobic effect, density
References: Hydrophobic Effect: http://en.wikipedia.org/wiki/Hydrophobic_effect
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