Final answer:
A styrofoam calorimeter features two holes, one for inserting a thermometer to measure temperature changes and another for using a stirrer to mix the reactants within the calorimeter for accurate readings.
Step-by-step explanation:
The two separate holes in a styrofoam calorimeter have distinct purposes. One hole is designed to hold a thermometer which measures the temperature changes during a chemical reaction or process within the calorimeter. The other hole is used for a stirrer, which ensures that the reactants within the calorimeter are evenly mixed and that the temperature throughout the substance is consistent for an accurate measurement. It is important to have these two separate holes rather than one, as each serves a different function and both contribute to the proper use and accuracy of the calorimeter in a laboratory setting.