A calorimeter is used to measure the heat and energy of a substance. This is the instrument that gathers the results. Heat comes from the atoms in a substance. Energy is defined as that heat plus any other potential energy, or "by-products" of the reaction of the atom. If you shine a light on a thermostat, it'll turn on when the temperature reaches 70 degrees Celsius. For this experiment, we have all kinds of equipment available to us: a thermometer and a calorimeter; and in addition to that, we have some sort of wires for holding the test material to carry heat out of it.