8I Heat Flashcards
How does heat energy flow
Flows from a hot object to a cool one
What is conduction.
When heat energy is transferred through particles touching each other and not moving . On,y works in solids
Why are carpets good insulators
Contain trapped heat so the particles carrying heat energy don’t escape
Explain in terms of particles ,pathetic transfer of heat energy in solids and why it expands
The particles gain more energy and vibrate more , they touch and pass the energy on . The extra vibrations means it needs more space to move so the solid expands ,
How does heat energy travel through fluids
When a fluid is heated the particles move around faster and expand so becom less dense . This is because the same mass is taking up a larger are of space . The heated particles begin to rise as they are less dense than the cool fluid around it . The cool fluid then takes its place and gets heated upb.
Describe a convection current in heating water
The water becomes warmer than the other parts so becomes less dense and starts to rise . As it nears the top it is pushed aside by other warm water particles rising . It starts to sink as it had transferred some energy to the other particles and starts to sink
Describe a convection current of a ice lolly
Heat is transferred from the air to the lolly , the air cools down . The cool air contracts so it is denser and sinks . Warm air takes the place of the sinking air
Changing from a solid to a liquid requires
Energy to break the bonds
In a vacuum heat travels through
Radiation
Radiation doesn’t need
A medium to travel through
When radiation hits something it can either
Be absorbed or reflected
What type of materials reflect heat energy
Light colours shiny materials
Which process do all objects use for transferring heat
Radiation
Which process transfers heat through invisible waves
Radiation
What is it called when two objects reach the same temparatur e
Thermal equilibrium
