1. Principles of Technology Waxahachie High School Ratein Thermal Systems PIC Chapter 3.4 Ratein Thermal Systems PIC Chapter 3.4 PT TEKS

2. Rate in Thermal Systems : Objectives:   Define heat flow and its SI and English units of measure   Describe the heat transfer processes of conduction, convection, and radiation   Solve heat transfer rate problems using the heat conduction equation : Objectives:   Define heat flow and its SI and English units of measure   Describe the heat transfer processes of conduction, convection, and radiation   Solve heat transfer rate problems using the heat conduction equation

3. Rate in Thermal Systems

5. When heat is transferred to a colder object, the atoms vibrate faster and faster as the temperature increases. The transfer of thermal energy arising from a temperature difference between adjacent parts of an object is called heat conduction. Rate in Thermal Systems

6. For heat conduction to take place, there must be a temperature difference within the object. The thermal conductivity (k) of a material is a measure of its ability to conduct heat. Rate in Thermal Systems

9. Convection is a transfer of heat by movement of fluid. The circulation of fluid by the transfer of energy due to temperature differences is called natural convection. Rate in Thermal Systems

10. When natural convection takes place in the Earth’s atmosphere it causes wind. When convection is forced by a fan or pump it is called forced convection. Rate in Thermal Systems

11. All objects radiate energy in the form of electromagnetic radiation. The rate of energy radiated by an object depends on the object’s temperature, area, and type of material. Rate in Thermal Systems

12. Radiation transfers energy from one body to another through empty space. A hot object radiates energy, some of which is absorbed by a cooler object. The cooler object also radiates energy but not as much as the hot object and so it absorbs more energy than it gives off. Energy is transferred from the sun to all planets in the solar system by radiation. Rate in Thermal Systems