P1.1 - Heat & P1.2 - Energy & Efficiency Flashcards
What is infrared radiation?
Heat from radiation
What is the difference between shiny, light surfaces and black, matt surfaces in terms of heat?
Shiny, light surfaces absorb more
Black, matt surfaces emit more
How do objects heat and cool in terms of energy transfer?
If emits faster than absorbs -> cools
If emits slower than absorbs -> warms
Explain melting in terms of particles
Heated particles vibrate, so bonds weaken:
solid -> liquid
Explain boiling in terms of particles
Heated particles vibrate, bonds break and move randomly
What does a u-value measure?
The speed heat travels through a material
Lower u-value = better insulator
How can insulation pay for itself?
Low u-value walls and windows reduce heat loss
-> saves on heating cost
Eventually the money it saves = cost of insulation/ double glazing
How do solar panels work?
Solar panels use sun heat to heat water tubes -> hot water tank
Renewable energy - works best on sunny days
What is specific heat capacity?
Energy needed to increase temperature of 1kg of a substance by 1°C
What is the law of energy conservation?
Energy can’t be made or destroyed, only converted
Describe energy changes in a car
Chemical -> kinetic + heat
What does a sankey diagram show?
Energy transfer in a process
