A burette is a glass tube that is open at the top and comes to a pointed narrow opening at the bottom. Right above the bottom opening is a stopcock that can be turned to control the amount of liquid being released. There are markings along the length of the tube that indicate the volume of liquid present.
A burette is used for extremely accurate addition of liquid. By adjusting the stopcock, the amount of liquid that is released can be slowed to a drop every few seconds. Burets are one of the most accurate tools in the lab.
Burets are set up by using a buret clamp in combination with a ring stand. (Discussed below)
To determine how much liquid is added, write down how much is initially in the buret. Then when finished adding, write down how much is left. Subtract the final amount from the initial amount and you have the volume of liquid added.
Remember to measure from the bottom of the meniscus!