Every mom knows about stuff that sticks – gum, candy, whatever that gunk was that you cleaned off the television screen. Here’s a fun (and not messy) way to demonstrate the sticking force between water molecules. This is what you’ll need:

Pepper Experiment Supplies

Supplies:

  • A large bowl
  • A small bowl
  • Pepper
  • Dish soap
  • Water

Directions:

  1. Fill a large bowl a little more than half full of water.
  2. Pepper Experiment 1

  3. Add pepper. Lots and lots of pepper. The pepper will float because the water molecules are sticking together to create surface tension.
  4. Pepper Experiment 2

  5. Squirt a tiny bit of dish soap in a smaller bowl.
  6. Pepper Experiment 3

  7. Dip a finger in the dish soap.
  8. Pepper Experiment 4

  9. Touch the finger to the water.
  10. Pepper Experiment 5

  11. Watch the pepper scatter to the edges of the bowl.
  12. Pepper Experiment 6

Why did that happen? When you added the dish soap to the water, it weakened the surface tension. The water’s surface tension force is stronger than the detergent and water mixture’s force, so the water pulled away from the soap and took the pepper along for the ride!

Originally written for and posted on the now-defunct My OH! Momma website.