P2 - Energy transfer by heat Flashcards
How does a material conduct heat?
The vibrations of the particles collide with neighboring particles, transferring energy.
What materials are the best conductors?
Metals are better conductors than non-metals.
What is the thermal conductivity of a conductor?
Conductors have high conductivity.
What is the thermal conductivity of an insulator?
Insulators have low thermal conductivity.
Which way does heat energy move?
Hot to cold.
What is temperature?
Temperature is how hot or cold something is.
What is the unit for heat energy?
Joules
What is the unit for temperature?
°C (degrees celcius)
What is a better conductor a solid, liquid or gas?
Solids are better conductors as the particles are close together. Liquids and gases do not conduct very well.
Is air a conductor or insulator?
Air is a very good insulator.
What is specific heat capacity?
The energy required to heat a 1kg block of a material by 1°C.
If it takes more energy for a material to heat up does it have a higher or lower specific heat capacity?
Higher
What is the equation for specific heat capacity?
Energy transferred = mass x specific heat capacity x temperature change
ΔE (J) = m (kg) x c (J/kg°C) x Δθ (°C)
How does fibreglass loft insulation reduce heat loss in the home?
The fibres trap air and is therefore a good insulator, preventing heat transfer by conduction.
How does a cavity wall reduce heat loss?
The space between the two block is filled with foam that traps pockets of air and is a good insulator, preventing heat transfer by conduction.
