Objective:
-To show the current will take the path of least resistance, regardless of what movies may lead us to believe.
Apparatus:
- hairdryer
- clear plastic container
- element from electric water heater
Method:
Fill the container with tap water, enough to cover the body of the hair dryer when submerged. Turn on the hair dryer and submerge in the water. The hair dryer will continue to run and simply draw water through it, warming it up in the process. It is safe to also put your hand in the water to really demonstrate that there is very little voltage drop in the water.
Notes:
- After removing the hair dryer from the water, ensure that you move it around and leave it running for a while to remove excess water. If the dryer remains too wet, it may rust and the fan may seize.
- There really is a little voltage in the water, but if you want to be extra cautious, make sure you have insulating shoes and don’t touch any metal objects (like the faucet) while operating the demonstration.
- This is a great demo to ask students for predictions beforehand, and explanations after.