03. Heat and Temperature

The measure of the hotness or coldness of a body

Any physical property that changes measurably with temperature

*• Length of a column of liquid

• Electrical resistance

• Emf of a thermocouple

• Colour

• Volume of a gas at constant pressure

• Pressure of a gas at constant volume

*Learn*

Copper wire, Iron Wire
Cold Junction (Melting ice)
Hot Junction
Sensitive Voltmeter

*They will agree at 0 °C and 100 °C

They generally disagree at other temperatures because Thermometric Properties do not change proportionally with the same change in the degree of hotness

Each thermometer is correct on its own scale. No one reads the 'true value' for the temperature

The heat energy needed to change the temperature of an object by 1 K

The heat energy needed to change the temperature of 1 kg of a substance by 1 K

The amount of heat energy needed to change the state of a substance
without a change in temperature

The amount of heat energy needed to change the state of 1 kg of a substance
without a change in temperature

The amount of heat energy needed to change 1 kg of a substance
from a solid to a liquid
without a change in temperature

The amount of heat energy needed to change 1 kg of a substance
from a liquid to a gas
without a change in temperature

*Learn Diagram*

Transfers energy from a cooler region to a warmer one. Work must be done to bring this about. It is used in refrigerators and in air conditioning systems in buildings and cars.

The circulating liquid has a high specific latent heat of vaporisation and a low boiling point

The transfer of heat energy through a substance
by the passing on of molecular vibration from molecule to molecule
with no overall motion of the substance

The rate of energy transfer through 1 m² of a surface when a temperature difference of 1 K is maintained across the surface.

the transfer of heat energy from one place to another by electromagnetic waves

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*Darker: more radiation
*Shiny: less radiation (I think)

The average amount of the Sun's energy falling per second
perpendicularly on 1 m² of the Earth's atmosphere.

Its value is 1.35 kW m⁻²

Solar Panels

Tubes to heat water p172 fig 15.12

the transfer of heat energy through a fluid
by using circulating currents of fluid.