p1.1-p1.3 Flashcards
Which surfaces absorb and emit infra red radiation the most?
Black matt surfaces
Which surfaces absorb and emit infra red radiation the least?
Light shiny surfaces
What colours absorb the most heat?
Dark
What colours reflect the most heat?
Light
What are the most efficient radiators made of?
Matt black materials
How do solar water heaters work?
Water pipes under a black surface
(zig zag pattern to increase SA)
Absorbs radiation from the sun (conduction)
Heats water (convection)
–> Water used for washing or pumped into radiators
Why are water pipes in a solar water heater in a zig-zag pattern?
To increase SA
–>Allows more conduction
What is heated water from a solar water heater used for?
Washing
Pumped into radiators
What happens to the amount of radiation that an object emits if it is hotter than it’s surroundings?
Emits more radiation than it absorbs
what happens to amount of radiation emitted by an object that is colder than its surroundings?
Emits less than it absorbs
Define a vacuum
A space with no particles
What are the three ways of transferring heat energy?
Conduction
Convection
Radiation
What two types of transferring heat energy uses particles?
Conduction
Convection
How is the speed of energy transferred by heating changed by the size of the difference in temp between an object and its surroundings?
Bigger temp difference=Faster
Which state of particles has the most density?
Solids
What state of particles has the most energy?
Gases
Use kinetic theory to describe the particles within a solid
Particles in a fixed, regular shape
Vibrate in position (only movement)
Strong forces of attraction at a distance
Repulsed when close together (–>so can’t be compressed)
Strong bonds between particles
–> shape is fixed, can’t be compressed
In what state of matter does conduction occur?
Solids
Liquids
Gases
What state and type of atom does conduction occur most efficiently?
Why?
Metals
Have free electrons
Describe the process of heat energy being transferred by conduction
Particles at one end are heated (+KE) -->Will vibrate (more the more energy recieved) -->Will knock into other particles -->Will transfer KE on
–>CREATES CHAIN REACTION–>energy spread through matter
Use kinetic theory to describe why gases are poor conductors
In gases: lots of space between particles
–>Less likely to knock into each other and transfer KE
How does double glazing work?
Air between two sheets of glass
–>minimises conduction of heat through the glass
Why do particles change state when heated?
More energy=more movement
- ->Eventually: will break free of bonds holding them in a fixed/random position
- ->BECOMES LESS DENSE AS MOVE AWAY FROM EACH OTHER
Use kinetic theory to explain how particles in a liquid are arranged and how this affects their properties
Arranged in random patterns
Medium forces between particles
–>little space between particles (hard to compress)
Have medium amounts of energy
–>Slide past each other (ALWAYS TOUCHING OTHER PARTICLES)
(FLUID)