Question

Why should we not use our mouths to provide suction for pipettes?

Answer 1

It would be wrong.

Explanation:

A cap either screws on or snaps on and is not flexible, meaning it cannot be used to create suction and draw a liquid out of a container, such as a test tube. A bulb is flexible and can be used to create suction and draw a liquid out of a container.

Answer 2

Well, it is a bit of a safety breach, and potentially hazardous.

Explanation:

I have heard of people who work in biological labs sucking up hepatitis cultures back in the day, when we used our mouths to provide the suction for a pipette (this was not so much an issue in a chemical lab). These days, we would routinely use a `"pipette bulb"`, and of course in a laboratory, these grow legs, and can even walk to other labs in the department. Neat trick, that!

Can you see where the legs might grow? I can't, but these things do tend to disappear in laboratories.

I use to keep these things in the pockets of my lab coat: