Science has never been so easy—or so much fun! With The Everything Kids' Science Experiments Book, all you need to do is gather a few household items and you can recreate dozens of mind-blowing, kid-tested science experiments. High school science teacher Tom Robinson shows you how to expand your sc...

OTC's No. 4619 Professional Battery Hydrometer displays a batteries specific gravity (density) on an easy-to-read float with a scale ranging from 1.100 to 1.300. Hydrometers are used to test the state of charge of a battery cell. This is performed by measuring the density of the electrolyte, which i...