Hands-on learning awaits...

Having trouble getting your kids to wash their hands thoroughly with soap? Try this fun experiment at home with simple household materials!

  • Plate or bowl
  • Water
  • Dish Soap
  • Pepper
Pour water into your bowl and then shake some pepper into it.
Take your finger and stick it into the water and pepper. Notice how the pepper sticks to your finger.
Wash your hands or put soap onto your finger. Put your finger back into the bowl and watch how the pepper moves to the side of the plate.
What’s the Science?
Water molecules like to cling to each other, which creates surface tension. Pepper is not attracted to water, so the pepper floats on top of the surface of the water due to the surface tension.
When you stick your finger that isn’t clean in there, the pepper sticks to your hand. When you use soap, it quickly moves away. Why? Soap is created to break surface tension so that it can clean objects. Thus, the water molecules carry the pepper with them as the tension is broken.