Mad Science of Sacramento Valley - Static Attractions!
Channel: Mad Science of Sacramento Valley
Date: 2013-12-03

What you need:

Thread
Plastic drinking straw
Plastic pen
A friend to help
Rug or carpet


What you do:

1. Tie a piece of thread around the middle of a straw.
2. Rub a pen on a rug until it feels warm (you are building up a charge).
3. Ask a friend to hold the free end of the thread and adjust the straw so that it is balanced at the end of the string.
4. Wait until the straw is still, and then bring the "charged" pen close to the end of the straw. What happens?


What's going on?

You made an electroscope! Electroscopes can detect charges like static electricity. Static electricity stays on an object - which is why it is called static - until it is discharged onto another object. Rubbing your feet on a carpet builds up static electricity and touching a doorknob discharges it. This is why you get a shock.

When you rub a pen on a rub, you charge up the plastic pen with static electricity. Charges can be positive or negative. The charge on glass and plastic tends to be negative. Your pen is also full of negative charges from being rubbed on the rug. Opposite charges attract and likes ones repel. Your pen repels the negatively charged electroscope, making it move!

Now try this:

Repeat the experiment using and unlit tapered candle instead of the pen. Does the candle have the same effects as the straw?



Mad Science of Sacramento Valley
(916)779-0390
Sacramento.MadScience.org
info@madsciencesacto.com
Serving Placer, El Dorado, Solano, Amador, Sutter, San Joaquin, Yolo and Sacramento Counties!!!