First you need to gather up all of the materials you will need. Below is a list of the following items needed to conduct this project: • 3 hearing aids • 3 hearing aid batteries to fit the above hearing aids • A refrigerator • A freezer • 2 refrigerator/freezer thermometers • A battery tester • A hearing aid dehumidifier Are you ready? Let’s get started. We will test the batteries in 3 different situations. The first is at room temperature. Basically just leave this battery out and test it at the same time the other two batteries are tested. The second battery is placed in the refrigerator at a constant temperature (you will need to place the thermometer in the refrigerator to record the temps at every testing). And the third battery is placed in the freezer (you’ll need a thermometer for the freezer as well). Test the voltage of all 3 batteries at the same time each day 3 times a day until the batteries and hearing aids are no longer working. Each evening place the batteries from the refrigerator and freezer in the hearing aid dehumidifier to remove all of the moisture from the hearing aid. What happened? What is your conclusion for this test? In most cases the colder temperatures will negatively affect the life of the hearing aid battery even though the moisture from the colder temperatures is removed each night. When compared to the manufacturer’s recommended battery life, the battery that was in the refrigerator lost 31 hours of life and the battery that was in the freezer lost 151 hours of life.