Test tube
A test tube is a thin glass tube that is closed and rounded at one end.
What is it for?
Scientists use test tubes to mix tiny amounts of chemicals and watch what happens, which is safer and saves materials.
How to use it
Fill it no more than a third of the way, so there is room to shake it gently or heat it.
🥽 Safety tip: When a test tube is being heated, point the open end away from yourself and everyone else.
Fun fact from Fizzy: Many test tubes are made from a special glass called borosilicate glass, which can be heated quickly without cracking.
A closer look
Test tubes are small on purpose. Using only a few drops or a pinch of powder means that if a reaction fizzes or changes colour, it stays small and easy to control. It also means you can try lots of experiments without using up your chemicals.
A slightly bigger, thicker version called a boiling tube is used when something needs to be heated strongly. Test tubes are cleaned with a long, bendy brush that reaches right down to the rounded end.
Where you would see one
Test tubes are used in school labs, in hospitals for blood and other samples, and in labs that test soil and water. Many hospital tubes are plastic, with coloured caps that show what test each sample is for.