Question: Do you use mercury in microscopes??

Angus Cook answered on 16 Jun 2016:

We do actually use mercury in the lab, but not in the microscope. We use it in something called a Reference Electrode. We always want to see how a metal will rust under different conditions, and sometimes we want to see what will happen if we wire the metal up to a power source (like a battery) and dunk it in salt-water.

The trouble is, we don’t always know how strong the power source is. If we put a Reference Electrode in the salt water along with the metal, we can measure how strong the power source is, and if it changes while the metal is rusting.

The mercury is in a mixture with chlorine, which we call ‘Calomel’. We have to be careful with the Reference Electrode because it’s made of glass, and if we break it then we can get mercury everywhere, which would be a problem because it’s not very good for you.

The time that you might use mercury in a microscope is in the lamp (you usually need to light up the thing you’re looking at, after all). Some lamps use a a gas containing mercury to emit a very distinct kind of light, which you might need sometimes if you want a very specific colour.