You will observe temperature changes as various salts are dissolved in water and determine which of them would make the best heat pack.

you will be working with the following reagents and glassware: nacl, kcl, cacl2 (enough of each to fill ~1 cm in the bottom of a test tube), distilled water (enough to fill ~2 cm of bottom of test tube), 2 test tubes per salt, thermometer, glass stirring rod
using these materials, design experiments to determine which salts dissolve exothermically and which dissolve endothermically.