Heat radiation Flashcards
How many different ways can heat be transferred ?
What are the ways?
Heat can be transferred through three ways.
Through radiation, conduction or convection.
How can heat energy be transferred?
Through infrared radiation.
What does convection and conduction involve?
The transfer of particles.
What is the main form of heat transfer in solids?
Conduction.
What is the main form of heat transfer in liquids and gasses?
Convection.
What can infrared radiation be emitted by?
Solids, liquids and gasses.
Fact about infrared radiation.
Any object can emit or absorb infrared radiation.
The bigger the temperature difference (between a body and its surroundings)…
The faster energy is transferred by heating.
What is infrared radiation emitted from?
The surface of an object.
What does an object that is hotter than its surrounding do?
Emits more radiation than it absorbs (as it cools down).
What does an object that is cooler than its surroundings do?
Absorbs more radiation than it emits (as it warms up).
The hotel an object…
The more radiation it radiates at a given time.
What surfaces absorb infrared radiation best?
Dark and matt surfaces. (also emit more infrared radiation).
What surfaces reflect infrared radiation best?
Light, shiny surfaces. Vacuum flasks have shiny inner surfaces to keep heat in or out, depending on whether the liquid is hot or cold.
How do solar water panels work?
- they contain water pipes under a black surface.
- radiation from the Sun is absorbed by the black surface to heat the in the pipes
- water can be used for washing or pumped to radiators to heat the building.
