How Much Heat Will It Hold?
Students learn about heat flows and how different materials absorb and hold heat at different ratesCopyright 2010, KVDP, https://commons.wikimedia.org/wiki/File:HeatAndColdStorageWithHeatPump.svg
Students relate thermal energy to heat capacity by comparing the heat capacities of different materials and graphing the change in temperature over time for a specific material. Students learn why heat capacity is an important property of thermal energy that engineers use in many applications.
For safety, engineers must understand the heat capacity of insulators and conductors. They wear rubber gloves, as an insulator, when measuring volts and amps through a metal wire with a low-heat capacity. When designing any electrical system (computers, buildings, motors, etc.), engineers keep heat capacity in mind to avoid causing short circuits in the equipment or shocking people who perform equipment maintenance. Engineers who design passive solar heating systems take advantage of the natural heat capacity characteristics of materials. They build into structures some thermal mass, usually made from a high-heat capacity material such as masonry, concrete or water that can store the sun's heat energy for an extended time and release it slowly after the sun sets, to prevent rapid temperature fluctuations. Engineers also consider heat capacity and thermal energy when they design food containers and household appliances.
After this activity, students should be able to:
- Define heat capacity.
- Measure the temperature of a material over time.
- Describe the difference between materials with high-heat capacity and low-heat capacity.
- Explain why engineers need to know about the heat capacity of materials when designing equipment, structures and products.