Physics Van 3-site Navigational Menu

Physics Van Navigational Menu

Q & A: Cool Current

Learn more physics!

Most recent answer: 10/22/2007
Q:
What happens if you put an electrical wire in liquid nitrogen
- Cathy (age 6)
Urbana IL
A:
Dear Cathy

Thank you for your question, it's a very good one.
Electrical wires are used to carry electricity. You could say that the electricity flows inside a wire the same way that water flows in a tube. If you have a big fat tube, you can send more water through it than you can through a skinny tube. In the same way, a fat wire can carry more electricity than a skinny wire.


OK, so what does this have to do with putting a wire in liquid nitrogen? Well, it turns out that liquid nitrogen is very very cold stuff (hundreds of degrees below zero). It also turns out that when you make a wire cold, it makes it easier for electricity to flow through the wire, (in the same way that making a wire fat will make it easier for electricity to flow through it).


So, putting a wire in liquid nitrogen will make it very cold, which will make it easier for it to carry electricity. (It will also make it harder to bend, but that's another question).

(published on 10/22/2007)

Follow-up on this answer.