Physics P1: Conduction and convection

What is conduction?

The process where vibrating particles transfer energy to neighbouring particles.

What is convection?

Where energetic particles move away from hotter to cooler regions.

Energy transferred to an object by heating is transferred to the thermal energy store of the object, which energy store is this energy shared across the object by?

Kinetic.

What causes energy to be passed between particles in a heated object?

Collisions between more energetic particles cause kinetic energy to be passed.

Where is the energy transferred once the object is fully heated?

The thermal energy stores of the surroundings or other touching objects.

What is the measure of how quickly thermal energy is transferred through conduction?

Thermal conductivity.

What state is an object usually in when conduction happens?

Solid.

Which two states do substances have to be in for convection to happen?

Liquid or gas.

What happens when a liquid or gas is heated?

The particles move faster, causing the space between them to increase.

What does this cause?

The density to decrease.

Fill in the blanks:

Because liquids and gases ________, the the warmer and less dense region will ________ ________ the denser, cooler regions and a convection current is created.

flow, rise, above.

How does a radiator rely on convection currents?

By heating up particles close to the radiator (decreasing their density and causing them to rise), they are spread out into the room, meaning colder, denser particles replace them by sinking, which are then also heated and rise. This forms a cycle where particles are heated and cooled around the room.

Why do liquids and gases more commonly transfer energy by convection instead of conduction?

Because the particles are free to move.