Energy 1 Flashcards
What 3 ways is heat energy transferred?
Radiation, Conduction or Convestion
How is heat radiation transferred?
It is transferred by INFARED (IR) RADIATION
How is conduction and convection heat transferred?
It is transferred of energy by PARTICLES
How is heat transferred in solids?
By CONDUCTION
How is heat transferred in liquids and gases?
By CONVECTION
Can solids, liquids or gases emit infared radiation?
All three can emit infared radiation
Can any object be absorb and emit infrared radiation?
Yes ANY object can both absorb and emit infrared radiation whether or not CONDUCTION or CONVECTION is taking place.
The bigger the temperature difference between a body and its surroundings the faster ……….?
……… energy is transferred by heating
All objects are continually emitting and absorbing…….?
……infrared radiation.
Infrared radiation is emitted from the surface of an object.
An object that’s hotter than its surroundings emits…..?
……more radiation than it absorbs (as it cools down).
An object that’s cooler than its surroundings absorbs ….?
……..more radiation than it emits (as it warms up)
The hotter an object is, the more radiation……..?
….it radiates in a given time.
What colour surfaces absorb infrared radiation the best?
Dark, matt surfaces are much better at absorbing infrared radiation than gloss white or silver surfaces.
What colour surface emits more infrared radiation at any given temperature?
Dark, matt coloured surfaces.
What colour surface reflect a lot of the infrared radiation the best?
Light shiny surfaces REFLECT a lot of the infrared radiation fallen on them.
Give an example of how you could use a light shiny surface to reflect infrared radiation.
A vacuum flask which will have an inner silver surface.
Give an example of how you could use a dark matt surface to absorb infrared radiation
A solar hot water panel contains water pipes under a black surface so that it ABSORB more heat thereby heating the water from radiation from the sun.
What is kinetic theory is simple terms?
It describes how particles move in solids, liquids and gases
What are the three states of matter?
Solid, liquid or gas
Explain kinetic theory in relation to solids.
Solids have STONG FORCES of ATTRACTION which hold the particles CLOSE TOGETHER in a FIXED REGULAR arrangement.
The parcels don’t have much energy so they can only VIBRATE about their FIXED positions.
Explain kinetic theory in relation to liquids?
Liquids have WEAKER FORCES of attraction between the particles. The particles are CLOSE TOGETHER but can MOVE PAST EACH OTHER, and form IRREGULAR arrangements.
They have MORE ENERGY than particles in a SOLID. They move in RANDOM DIRECTIONS at LOW SPEEDS.
Explain kinetic theory in relation to gases?
Gases have ALMOST NO forces of attraction between the particles. The particles have MORE ENERGY than those in liquids or solids - they are FREE TO MOVE and travel in RANDOM DIRECTIONS at HIGH SPEEDS
What happens when you heat a substance in relation to kinetic energy?
Heating a substance gives its particles MORE KINETIC ENERGY (KE) - they vibrate or move faster.
This is what eventually causes solids to melt and liquids to boil
Conduction of heat occurs in solid, liquid or gas?
Conduction of heat usually occurs in solids
Describe the process of conduction by heat energy?
Conduction of Heat Energy is the process where VIBRATING PARTICLES pass on their EXTRA KINETIC ENERGY to NEIGHBOURING PARTICLES.
Eventually the EXTRA KINETIC ENERGY passes all the way through the solid causing a rip in temperature at the side of the solid.
How does the density of a solid affect conduction of heat?
The denser the solid the faster conduction takes place because the particles are closer together and so will collide more often and pass energy though them.
How does an insulator work in relation to conduction?
An insulator has LARGER SPACES between their particles so conducting heat energy is MUCH SLOWER.
Why are metals good conductors?
- The electrons in metals are free to move inside the metal.
- At the HOT END the electrons move faster and collide with other FREE ELECTRONS, TRANSFERRING ENERGY.
- Because the electrons move FREELY this is a faster way of transferring the energy which is why heat travels so FAST through METALS
Which is a is a more efficient conductor: a short fat rod or a long thin rod?
A short fat rod because the electrons have less distance to travel (i.e. shorter distance to transfer energy).
