Convection Flashcards
Conduction
How heat is transferred through solids
What happens when a material is heated?
When a materials is heated the particles become energetic and vibrate. It melts.
Expansion- the particles take up more room
What happens when a material becomes a solid?
It contracts, its particles lose kinetic energy. The decreased kinetic energy let’s the particles come closer together
Expansion and contraction
When substances expand or contract, their particles stay the same size it’s the space between them that changes.
Convection currents Mineshaft experiment
- The candle heats up the air.
- The hot air expands and so becomes less dense and begins to rise.
- Cooler more dense air sinks to replace the hot air and so a convection current is formed.
The heat goes from the candle into the tube.
Heat is being transferred from the candle flame to the particles.
Why does smoke rise?
The smoke rises because it has been heated by the fire so then it would be expand, become less dense and rise.
Why does the ballon rise?
The balloon rises because the fire is heating up the air and the hot air expands causing it to rise and making the balloon rise up.
Why does the hang glider rise?
Thermals are underneath the wings and hot air rises so the glider does too.
Thermals
Thermals are columns of hot air that are heated by the sun due to the unevenness of the planet.
Why is the ice box at the top?
Because the cold air will sink and push the warmer air upwards.
Why is the heater at the bottom?
It would heat up the whole of the heater/kettle (and the rest of the room)because hot air rises
Convection definition
Convection is the transfer of heat by the movement of fluid (liquid or gas) between areas of different temperature
Domestic central heating
Water is used in domestic central heating set up and water flows around the house through all the radiators which is heated by the boiler and is responsible for the hot water in the house.
why are there gaps between the railway lines?
because they expand in the Summer due to the heat and the railway would buckle possible derailing the train
when the line on a graph which is describing temperature change is straight what does that mean?
it means that a change of state is occurring
