The Digital Bits Science Labs are fun science experiments for young children. Kids, make sure you have an adult's permission before trying any of these science experiments.
Digital Bits Science Lab
Science Experiments for Kids, Parents and Teachers
Demonstration of surface tension
Description:
See surface tension in action – what happens when you turn it on, and what happens when you turn it off!
Equipment needed:
A wide bowl filled with water
Several index cards
Scissors
Liquid dishwashing soap
An eye dropper, or medicine dropper
The Digital Bits Science Lab Experiment:
Cut an index card into confetti: cut it into strips, then cut those strips into squares. The squares should be no larger than a half-inch on a side.
Mix up the confetti. Make sure none of the pieces are sticking to each other.
Suck a couple drops of liquid soap into the eye dropper.
Sprinkle the confetti in the bowl of water:
Then, use the eye dropper to squeeze one drop of liquid soap directly into the middle of the bowl. Once the soap hits the water, the pieces of paper will fly towards the side of the bowl:
What’s happening? When we drop the soap into the water, it breaks the water’s surface tension right where the soap landed. Think of the surface of the water as a balloon, stretched tight. When the surface tension breaks, the balloon “pops”, and pulls itself away from the break, taking the confetti with it.
If you want to do this experiment again, you’ll need to make sure that any soap is completely washed off any bowl you use. So either use a different bowl, or be sure to wash all the soap off the original one.
Other articles related to this topic:
- Power a boat with surface tension: Make a “zoomer”
- How to join and separate two streams of water – surface tension in action
- Move a stream of water with a balloon and static electricity
- Heat conduction with water, balloon and candle
- Hot air takes up more space than cold air
This is a version of the old “Magic Finger” trick, which I learned as follows:
Sprinkle pepper all over the surface of a saucer of water (just a substitute for the confetti). Before the trick, spread a drop of the liquid soap over one fingertip. If demonstrating as a magic trick, have one bystander stick a finger into the bowl and note that nothing happens. Then, stick your “magic finger” into the water and watch the pepper fly to the sides.