Goal
You will make your own electroscope and test the ability of various materials to conduct static electricity. You will also make a list or triboelectric series that organizes materials according to their ability to conduct electrons.
Introduction
When electrical charge builds up on an object, it is called static electricity. Sometimes this static electricity can suddenly discharge, as seen in lightning in the sky. At other times, this static electricity causes a static cling that is seen on socks fresh from the dryer. Static cling occurs when two objects that have different charges, such as positive (+) and negative (-), stick together. Static electricity can be produced and tested using various science fair experiments.
During science fair experiments, static electricity can be measured with an electroscope. You will build your own electroscope to test various materials and discover which ones conduct the most static electricity.
Materials
foam plate, balloon, foam cup, clay, drinking straw, aluminum cake pan, aluminum foil, string, wooden ruler, adhesive tape, different materials for testing, such as nylon, polyester, cotton, aluminum, plastic, copper, wool, tissue paper, saran wrap, and so on.
Preparation
making your electroscope
Pierce a Styrofoam cup by pushing a skewer near the base and poke holes for a straw to pass through. Thread a straw through the cup by placing it in these holes and push it in until it sticks out the side. Now turn the cup upside down and glue it down tightly with clay into a vertical cake pan.
Tie a few knots in one end of a thread and make a marble-sized ball out of a piece of aluminum foil at the knotted end. Now tape the free end of the string to the straw sticking out of the glass in such a way that the ball hangs from the straw and touches the edge of the cake pan. Secure the straw with a ribbon so it doesn’t move.
testing your electroscope
One of the methods used in science fair experiments to create a static electrical charge is to rub a piece of wool on a Styrofoam plate. This produces a negative charge on the surface of the Styrofoam plate. Now pick up your electroscope holding the Styrofoam cup and place it on top of the loaded Styrofoam plate. What happens? The ball of aluminum foil moves away from the edge of the cake pan.
Why did this happened? When he placed the electroscope on the Styrofoam plate, the negatively charged electrons traveled into the cake pan and then into the foil ball. Since the same charges repel each other, the ball moved away from the edge of the pan.
Now touch the pan and the foil ball with the tip of your finger and see what happens. The ball will return to normal as it was before, because the electrons have been transferred to your finger and the tray and ball have discharged.
Process
Now it’s time to try different materials.
- Charge different materials with static electricity. You can use materials like plastic wrap, a wool scarf, a wool sweater, aluminum foil, a balloon, etc.
- Now test each charged material with your electroscope.
- Measure how far the ball is from the pan with a ruler.
- Record the distance in a table.
- Take note of which materials can carry an electrical charge and which cannot.
- Since data logging is an important step in science fair experiments, you should order the data with the most loaded followed by the least loaded. This is called a triboelectric series.
Now that you’re equipped with some great ideas, I’d like to give you something else to ensure your success. Here’s your free copy of “Simple Steps for Award-Winning Science Fair Projects,” which you can download immediately from the link below.
