P1 Flashcards
How can you increase the rate of energy transfer (make things hotter quick or cooler quicker)
o Increase surface area
o Use dark matt colours
How can you decrease the rate of energy transfer (keep things hot)
o Decrease surface area
o Use shiny silver surfaces
What are the key points about infrared radiation?
o Black matt surfaces are the best absorbers and emitters
o Shiny silver are the worst absorbers and emitters
o The hotter the object the more infrared radiation is emitted
o IR is part of the electromagnetic spectrum
o Discovered by putting a thermometer past the red section of a light spectrum
o IR used in remote controls, thermal imaging, optical fibres.
o It is absorbed by the skin and can damage or kill skin cells because it heats up the cells.
Describe the difference between the solid, liquid and gas states, in terms of the arrangement and movement of their particles.
Solid – particles vibrate about fixed positions, closely packed, strong forces of attraction
Liquid- move at random but in contact with each other
Gas – particles move randomly, far apart
Explain how energy is conducted through a substance. (3 marks)
o Particles gain kinetic energy
o And vibrate faster
o The energy is passed on from atom to atom by collisions
Explain how energy is conducted through a metal. (4 marks)
o Metals have free electrons
o The electrons gain energy and vibrate faster.
o The electrons transfer energy to other electrons/ions/atoms
o by collisions
• Explain how a convection current is set up in a fluid (liquid or gas)
o The particles gain energy
o The particles spread out
o The (insert name of fluid) becomes less dense
o The hot (insert name of fluid) rises
o The cooler, denser (insert name of fluid) falls
o REMEMBER HEAT RISES = 0 MARKS
List the factors affecting the rate of evaporation
o Surface area
o Temperature
o Draught across the surface of the liquid
(Think wet washing in a bag versus washing hung out on a hot, breezy day)
List the factors affecting the rate of condensation.
o Surface area
o Temperature
Explain how condensation forms on a surface.
o Water evaporates o Water particles go into the air o The surface is cooler than the air o The water particles lose energy o Causing condensation on the mirror
Explain how the evaporation of a liquid causes the temperature of the remaining liquid to decrease.
o The particles with more energy
o Leave the surface of the liquid
o Which reduces the average kinetic energy of the remaining particles.
