P2 - Energy transfer by Heating

What material is the best at conducting energy?

Metal

What materials are the best insulators?

wool and fibreglass

What does the energy transfer by conduction through a material depend on?

its thermal conductivity

What three factors does energy transfer through a layer of material depend on?

- the temperature difference across the material
- The thickness of the material
- The thermal conductivity of the material

What type of radiation does all types of objects emit and absorb?

infared radiation

The hotter an object is...

The more infared radiation it emits.

What is blackbody radiation?

Radiation emitted by a body that absorbs all the radiation incident on it

The temperature of an object increases if...

it absorbs more radiation than it emits.

What two factors does the earth's temperature depend on?

The absorption of infared radiation from the Sun

the emission of radiation from the earth's atmosphere and surface.

What is the definition of specific heat capacity?

The specific heat capacity of a substance is the amount of energy needed to change the temperature of 1kg of a substance by 1 degree.

The greater the mass of an object...

The more slowly its temperature increases.

What equipment is used to find the specific heat capacity?

joulemeter and thermometer

What heaters are used to warm up houses?

Electric and/or gas heaters and gas or oil fired central heating or solid-fuel stoves

How can the rate of energy transfer be reduced in a home?

Loft insulation, cavity wall insulation, double-glazed windows, alumnium foil behind the radiators, external walls with thicker bricks and lower thermal conductivity.

What is cavity wall insulation?

Insulation material that is used to fill the cavity between the two brick layers of an external house wall

What is conduction?

Conduction is the transfer of thermal energy through direct contact.

What is convection?

Convection is the transfer of thermal energy through the movement of a liquid or gas.

What is radiation?

Radiation is the transfer of thermal energy through thermal emission.