Burette
A burette is a very long, thin glass tube with a scale and a little tap at the bottom.
What is it for?
It lets liquid out very slowly and measures exactly how much has come out.
How to use it
It is clamped upright on a stand. Turn the tap to let the liquid drip out, and read the scale before and after.
🥽 Safety tip: Fill it using a small funnel while it is below your eye level, so nothing can spill onto your face.
Fun fact from Fizzy: Chemists use burettes for titration, a way of finding out exactly how strong an acid is.
How a titration works
In a titration, a measured amount of acid goes in a conical flask with a few drops of indicator. An alkali is added from the burette, drop by drop, while the flask is swirled. The moment the indicator changes colour, the tap is closed.
The difference between the burette readings at the start and the end tells you exactly how much alkali was needed. From that, a chemist can work out how strong the acid was.
Where you would see one
Burettes are used by older students and by labs that check the strength of things like vinegar, fruit juice and the water in swimming pools. Their scale reads from top to bottom, the opposite way round from a measuring cylinder.