Test tubes are one of the most widely used tools for performing science experiments. In chemistry, the test tube is used to hold, mix or heat small quantities of chemicals while performing experiments. For biology, the test tube is used to handle and cultivate molds, bacteria, seedlings and plant cuttings. Assortment features 3 types of tubes: 6 glass tubes, 6 plastic tubes and 6 large, safety tubes with screw caps. Also includes an activity guide. For ages 7 and up.