Thermal Energy Transfer: Visualizing Radiation
Radiation is unlike conduction and convection. It transfers heat from one place to another through indirect interaction using waves. Read the passage below and watch the related video to learn more. After you've watched, read how scientists can "see" heat being emitted by objects.
Radiation
Radiation transfers heat by electromagnetic waves. Thermal radiation can carry energy through matter or through empty space. When electromagnetic radiation strikes an object, the particles in the object absorb energy from the electromagnetic waves and particle motion increases. For example, a microwave oven warms food by radiating electromagnetic waves that increase the motion of particles within the food.
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Video: Heat Transfer Through Radiation
All matter emits energy in infrared wavelengths, a specific region of the electromagnetic spectrum associated with heat. Human eyes cannot see these wavelengths, but by assigning colors to infrared radiation at particular wavelengths, false-color images can visually display differences in heat emitted by objects. Look at this example, which shows two cups with hot and cold drinks and their false-color thermal image. The hotter an object is, the more intensely it radiates infrared wavelengths.
Before moving on, use Arrange It to demonstrate your understanding of the three methods of heat transfer.
