Photo: Rich Evenhouse
Here’s another science experiment you can do at home. It’s fun, it’s easy, and it involves one of a kid’s favorite things: soap bubbles!
You’ll need a sheet of paper, a hairbrush and a table. Cover the table with a large piece of flannel or wool cloth. You’ll also need a young assistant with a bottle of soap-bubble fluid, available in any toy store.
Have your young assistant blow some soap bubbles gently onto the surface of your table. If you do it carefully you can get the bubbles to rest on the table cloth without popping.
Next, rub the hairbrush rapidly across the paper. Now pass the paper over the resting soap bubbles, and they will stretch into elongated shapes as it comes near. With a little practice, you can even get the bubbles to rise into the air and follow the paper! What’s going on here?
Rubbing the brush across the paper is just a quick way of knocking some of the electrons off. This causes some of the atoms in the paper to have a net electrical charge. Before, the paper was electrically neutral, and now it is positively charged. Charged atoms have a tendency to balance themselves out again, so that they are electrically neutral once more. That means the positively-charged atoms in the paper will now attract other atoms in a effort to snag their electrons away.
We can see this attraction working on the atoms in the bubbles. The bubbles are light and flexible enough to actually be drawn upward as the paper passes by, even to the point of floating in the air!