We've learned about how conductivity means how fast electricity goes through something,
and that metal is a good conductor, but rubber is a bad one, also known as a resistor.
What about things that are kind of good conductors?
We call those semiconductors.
One of the most common semiconductors out there is a chemical called silicon.
![silicon](https://upload.wikimedia.org/wikipedia/commons/thumb/2/2c/Silicon.jpg/480px-Silicon.jpg)
(from: wikipedia - semiconductor)