How can I create a DIY calorimeter for measuring heat energy in chemical reactions?

To create a DIY calorimeter for measuring heat energy in chemical reactions, you can use a simple setup with a Styrofoam cup, a thermometer, and a stirrer. Fill the cup with a known volume of water and measure its initial temperature. Then, add the reactants to the water and stir while monitoring the temperature change. By calculating the change in temperature and knowing the specific heat capacity of water, you can determine the heat energy released or absorbed during the reaction.