If you find beakers and test tubes limiting because of their shape and size, or if you are troubled by the visual distortion of those small containers, then you need to consider The Teaching Tank. Specially designed to eradicate those problems from your science labs, science experiments can become easier and far more exciting with the use of this tool. Two square sheets of clear acrylic (a little smaller than 12” x 12”) are fastened together, sandwiching a U-shaped rubber tubing spacer to create a roughly 10” x 10” x 1/4” tank, open at the top for experiments. The tank can be taken apart for easy cleaning or storage and then put back together. The expansion kit is a flexible gasket that fits between the acrylic sheets, expanding the volume of the tank to hold up to a gallon. The polyacrylamide crystals can be used for hydroponics experiments, water absorption, and many other activities. Crystals come in a 4-oz. bag. The tank (item # 015290) comes alone, with no crystals or activity books, but see the following descriptions for some great experiment books and check out the Teaching Tank Starter Kit for a great deal.