Materials:
- Old Golf tube, or some other large plastic tube
- Wool sock or shirt, or something to rub the tube with so it will acquire a charge
- 4″ diameter watch glass
- 8′ long or so two-by-four
- Place the watch glass on a table upside down so that the lip of the watch glass is flat on the table
- Balance the 2″ x 4″ on the inverted watch glass so that no part of the 2″ x 4″
- Rub the golf tube several times with the wool so that the tube acquires a negative charge
- Place the tube near, but not touching one end of the 2″ x 4″ and wait for a few seconds
- The tube will begin to attract the 2″ x 4″ continue to move the tube away from wood as the end of the wood follows, keeping the wood about a distance of 1″ to 2″ away from the end. If you want you can start the tube rotating in the other direction by placing the tube on the other side of the wood
Explanation:
The golf tube is negatively charged, and negatively charged objects can attract things that are both positive and neutral. Since the wood is neutral, the wood is attracted to the rod. The amount of friction that the 2″ x 4″ would normally experience is greatly reduced by allowing the 2″ x 4″ to pivot on the watch glass.
The reason neutral objects attract to uncharged objects is because all neutral objects are made up of an equal number of electrons and protons. The electrons surround the nucleus of the atom. As a negative object is brought near the atom, the electrons slightly shift their position around the outside of the atom to move away from the negative charge; therefore the end of the atoms closest to the negative charge is slightly positive. The positive charges are attracted to the negative tube and thus the wood is attracted to the tube.
Reinforcement Activities:
There are many fun electrostatic experiments that can be done. One of my personal favorites is using a Van de Graff Generator. The students are instantly engaged by something that can give off sparks. There are many fascinating demonstrations that can be done from making a student’s hair stand on end, to making cereal and metal pie tins fly around the room.
Investigate static electricity by using the tried and true tool of Benjamin Franklin, the electroscope. Have students create different charges and study their effects on the electroscope.
Create mini-lightening bolts in your classroom and learn about electric charge using a Wimshurst Static Machine. Sparks can be around four centimeters long!
Related Products
- Demonstration Wimshurst Static Machine
- Closed Case Form Electroscope
- Open Case Form Electroscope
- Large Electrostatic Generator with Discharger
- Van de Graaff Generator
- Class Size Electrostatic Kit
- Friction Rods (Solid Acrylic, Hollow Glass, Solid Glass, Solid Hard Rubber)
- Wool friction pad
