Test tube
A test tube is a kind of laboratory glassware, composed of a fingerlike length of glass tubing, open at the top, usually with a rounded lip at the top, and a rounded 'U' shaped bottom.
They range in size from a couple inches to several inches long, from a few millimeters to a couple centimeters in diameter. They are designed to allow easy heating of samples, to be held in a flame, and often are made of expansion-resistant glasses, such as borosilicate glass (known by brand-names such as Pyrex and Kimax).
Tests tubes are often preferred above beakers when multiple small chemical or biological samples have to be handled and/or stored.
Vacutainers are a type of test tube that can be used for both collection and storage of blood.
Test Tube Media
Louis Lumière with a microscope and some test tubes
Samples of human blood collected for blood tests
An illustration of a setup using an ignition tube. The ignition tube is being heated by the Bunsen burner on the left, with the heated gas escaping from the tube to the pan via the delivery tube on top and at right.
