Heat transfer
Heat moves by conduction (through touching matter), convection (moving fluid) and radiation (electromagnetic waves).
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Analogy
A pan handle, a boiling pot and the Sun's warmth show all three.
Example
Metal spoon: conductionBoiling water: convectionSunlight: radiation
In practice
The Sun warms Earth by radiation, because space has no matter to conduct heat.
Practice
Flashcards
- What are the three ways heat moves?Conduction, convection and radiation.
Questions people ask
Why do metals feel colder than wood at the same temperature?
Metal conducts heat away from your hand faster than wood does. Your skin senses the speed of heat loss, not the actual temperature. Both objects are at room temperature, but a metal handrail feels colder because it pulls warmth from you quickly.
How does a thermos flask keep drinks hot?
A vacuum layer between two walls stops conduction and convection. The walls are shiny silver to reflect radiation. The lid is made of insulating plastic to slow heat loss from the top. Together these reduce all three heat transfer methods.