1. Education

Test Tube

Chemistry Laboratory Glassware


Test tubes in a test tube rack.

Test tubes in a test tube rack.

TRBfoto, Getty Images
Test tubes are round-bottom cylinders, usually made of borosilicate glass so that they can withstand temperature changes and resist reaction with chemicals. In some cases, test tubes are made from plastic. Test tubes come in several sizes. The most common size is smaller than the test tube shown in this photo (18x150mm is a standard lab test tube size). Sometimes test tubes are called culture tubes. A culture tube is a test tube without a lip.

©2014 About.com. All rights reserved.