1729 – Conduction – Stephen Gray
Stephen Grey was a dyer by profession, but had interests in astronomy and natural sciences. His education was mostly self educated. We he retiremented he experimented with static electricity. In one experiment he used a glass tube which he kept the ends closed with cork, to keep the tube clean.
He noticed that when he rubbed the glass tube the cork, attracted items. He put a stick into the cork and was able to extend attraction. He began to do experiments to see how far he could extend the effects.
This was the beginning of experiments with conduction, the ability to move electrons through materials.
Experiment – Conduction
Items needed:
- Light weight objects, like small pieces of paper, crispy rice cerial, ground pepper, …
- 3 feet of 3/4 inch PVC pipe
- 3/4 inch corks
- 10 gauge insulted wire witwool, hair or fur
The experiment:
- place a cork in both ends of the pipe.
- Stripe enough wire to fit al the way through the cork and stripe about 1/2 inch from the other end of the wire.
- Poke one end through the cork at one end of the piple. (A hole may need to be drill, depending on how ard the cork is)
- Rub the pipe with the word, hair or fur. Build up a big charge.
- Slowly move the free end of the wire near the light weight objects
- Write down your observations.
Explanation:
The charge on the outside of the PVC pipe is negitively charged, this repells the electrons on the inside of the pipe, forcing electrons in the wire to be replelled. The electrons in the wire can move or conduct. The electrons in the wire, move to the far end of the wire and repell the electrons in the small objects, making the charge on the small objects near side to the wire become positive (lack of electrons), so they are attracted to the wire.