Flashcards
Heat Transfers ✔
Cards in this deck (15)
- 1What is the difference between heat and temperature?heat: the amount of thermal energy an object has
temperature: a way of measuring how hot or cold something is against an agreed scale - 2How is temperature measured?Using a thermometer in degrees Celcsius
- 3What measurement is heat measured in?In joules
- 4Define: i) conductor ii) insulator iii) conductioni) a material which allows energy to pass through, e.g. metal
ii) a material which does not allow heat to pass through it easily- e.g. wood/plastic
iii) when heat is transferred from a hot place to a colder place in an object - 5True or False: Conduction mainly happens in liquids.False.
Conduction mainly happens in solids since the particles are packed closely together and cannot move very well. - 6What happens during conduction? - read and remember:-A metal bar is heated.
-The heat energises the atoms and vibrations increase.
-The vibrations spread throughout the metal heating up the entire bar. - 7What is convection?When heat energy is transferred place to place through liquids and gases.
- 8What is a fluid?A gas or liquid.
- 9What is a convection current?The circulation of a fluid through convection
- 10Why does convection need fluids?In order for convection to happen, the particles in the material must be able to flow and move from place to place.
- 11What happens during convection? - read and remember:-Liquids and gases expand when heated.
-This is because the particles move faster when heated and they take up more volume.
-The fluid in hot areas is less dense than the fluid in the cold areas, so it rises and takes it place.
-The denser cooler fluid falls into the warm areas, which then also gets heated, and the cycle repeats. - 12What is radiation?The type of heat energy that comes from the Sun through electromagnetic waves.
- 13How can the heat travel through space during radiation?It can travel through space because- unlike convection or conduction- there are no particles involved.
- 14Heat radiation is carried by what?infra-red and ultra-violet rays
- 15Which surface best absorbs heat? a) a shiny, white surface OR b) a dull, dark surfaceb) is the best heat absorber