How to Read a Graduated Cylinder

What is a Graduated Cylinder?

A graduated cylinder is basically a test tube with volume markings. It has a spout for pouring and a built-in base so it can stand upright on its own. They measure volumes accurately if the reading technique is correct. The video below helps demonstrate this.

What is a Meniscus?

A meniscus occurs between a liquid and the air above. It always forms with a downward-facing curve whether it is coffee, milk, scotch or water.  You can see it in narrow vessels such as test tubes and graduated cylinders. It is not as apparent in a larger container such as a bucket. Water has a much higher surface tension than other liquids such as alcohol and produces a much more pronounced meniscus.

Graduated cylinders can measure volumes of liquid accurately. Indigo Class B cylinders are rated at 1% accuracy if read properly and is shown in the video below.

The bottom of the meniscus should line up with the cylinder’s calibration lines for an accurate reading. The video shows a 100 ml graduated cylinder in use where the viewing angle is level. This is compared to reading slightly above and below which is wrong.