P2.4 Energy transfers: particles Flashcards
Name a material that is a good conductor of electricity.
Metals and graphite are good conductors of electricity.
What is a conductor?
A conductor is a material that conducts charge or energy well, such as a metal or graphite.
What is conduction?
Conduction is a way in which energy is transferred through solids, and to a much lesser extent liquids and gases.
How do particles transfer energy in conduction?
In conduction, particles transfer energy by colliding with other particles when they vibrate.
When does energy transfer happen until?
Energy transfer happens until the two surfaces are at the same temperature.
What is an insulator?
An insulator is a material that does not conduct electricity or transfer energy well.
Name an example of an insulator.
An example of an insulator is e.g wood, or many non-metals.
Do insulators conduct any sort of energy?
Even though insulators are poor conductors of energy, that does not mean that they do not conduct at all, but that energy is transferred very slowly through them.
Why do gases not conduct electricity well?
Gases do not conduct well at all because their particles are much further apart than the particles in a solid.
What is convection?
Convection is the transfer of energy by the movements of gases or liquids.
What is a convection current?
A convection current is the movement of heated liquids or gases.
What is radiation?
Radiation is the transfer of energy as a wave.
In terms of particles and convection, explain in detail what happens when you heat soup in a pan.
When you heat soup in a pan it all heats up,not just the layer in contact with the bottom ofthe saucepan. This is what happens:
- The soup that is in contact with the bottom of the pan gets hotter so the particles there move faster
- The particles in the soup move further apart, so the soup becomes less dense
- The hotter soup rises and cooler, denser soup takes its place
What do solids transfer energy by?
Solids transfer energy by conduction.
What do liquids and gases transfer energy by?
Liquids and gases transfer energy by convection.
Give an example of something created by a convection current.
E.g hurricanes and winds are created by convection currents.
How is wind created?
Wind is created by convection currents along the shoreline/ coast.
Why are metals better conductors than other solids?
Metals are better conductors than most other solids because they have delocalized electrons flowing through them which further helps transfer the energy and heat via the vibrations even more.
Why are solids good at conducting?
Solids are good at conducting because their particles are packed very closely together and the particles touch their neighbors, which helps transfer the heat through vibrations.
Why can conduction only happen effectively through solids?
Conduction can only effectively happen through solids because their particles are very close together, which helps transfer the heat through vibrations. The particles in a fluid are too far apart to vibrate to transfer the energy.
What is a fluid?
A fluid is a gas or a liquid.
What is density?
Density is the number of particles in a given volume.
What is the equation of density?
Density = Mass / volume
Explain in terms of particles why convection happens in liquids and gases but not in solids.
The particles in a gas or in a liquid can move; the particles in a solid
cannot. Convection involves the movement of particles to transfer energy.
