Why are metals good conductors?
Because they have free electrons that transfer heat quickly.
Why are plastics used as insulators?
They do not allow heat to pass easily.
What happens to air when it is heated?
It expands and rises.
Name two machines that produce heat as a by-product.
Computers, refrigerators, microprocessors, engines.
Why does a microprocessor generate heat?
Because electrical energy is converted to heat during operation.
How does a refrigerator move heat?
It removes heat from inside and releases it outside.
Explain why turbines spin in a power plant.
Steam or gas expands, pushing the turbine blades.
What is absolute zero?
0 K or –273°C.
Why is safety clothing important in power plants?
To protect from heat, noise, and dangerous equipment.
What happens in the intake stage of a heat engine?
Air is drawn into the engine.
What happens during the exhaust stage?
Gases are expelled from the engine.
Give an example of convection from everyday life.
Steam rising from cooking food.
Give an example of conduction from everyday life.
A hot pan heating its handle.
Give an example of radiation from everyday life.
Heat from a fire felt without touching it.
What type of heat transfer does the sun use to warm Earth?
Radiation.
Why is Kelvin sometimes used instead of Celsius?
It starts at absolute zero; useful in scientific calculations.
