Criado por Farha Idrees
mais de 8 anos atrás
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Questão | Responda |
What 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 |
How is temperature measured? | Using a thermometer in degrees Celcsius |
What measurement is heat measured in? | In joules |
Define: i) conductor ii) insulator iii) conduction | i) 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 |
True 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. |
What 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. |
What is convection? | When heat energy is transferred place to place through liquids and gases. |
What is a fluid? | A gas or liquid. |
What is a convection current? | The circulation of a fluid through convection |
Why 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. |
What 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. |
What is radiation? | The type of heat energy that comes from the Sun through electromagnetic waves. |
How can the heat travel through space during radiation? | It can travel through space because- unlike convection or conduction- there are no particles involved. |
Heat radiation is carried by what? | infra-red and ultra-violet rays |
Which surface best absorbs heat? a) a shiny, white surface OR b) a dull, dark surface | b) is the best heat absorber |
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