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:
- A large bowl
- A small bowl
- Dish soap
- Fill a large bowl a little more than half full of water.
- Add pepper. Lots and lots of pepper. The pepper will float because the water molecules are sticking together to create surface tension.
- Squirt a tiny bit of dish soap in a smaller bowl.
- Dip a finger in the dish soap.
- Touch the finger to the water.
- Watch the pepper scatter to the edges of the bowl.
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 mixtureâ€™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.