Heat and Hemperature
- Heat- Heat is the measure of how much thermal energy is in an object
- Temperature- Temperature is the measure of how hot something is, it is measure in degrees celcius co
Thermal imaging cameras (Thermograms) detects for infrared radiation- the type of radiation that comes from all objects. The images that thermal imaging cameras produce are called thermograms. The colours that thermograms produce are indicators for how hot or cold something is.
- The hottest parts of the pictures are red, yellow or white.
- The coldest parts of the pictures are purple, dark blue or black.
Heat energy flows from a hot object too a cooler one.This causes:
- Hot objects to cool down
- cool objects to cool down.
When heat energy is transferred to an object, it incresases depends upon:
- The mass of the object.
- The substance the object is made from.
- The amount energy transgerred to the object.
For a particular object,the more heat energy transferred to it, the greater its temeperature increase.
Specific Heat Capacity
Specific Heat Capacity
The specific heat capacity of a substance is a measure of how much heat energy it can hold. It is the energy needed to increase the temerature of 1kg of a substance by 1 ºC. Different substances have different heat capacities.
A substance must absorb heat energy so that it can melt or boil. The temperature of the substance does not change during melting, boiling or freezing, even though energy is still being transferred.
A heating curve is a graph showing the temperature of a substance plotted against the amount of energy it has absorbed. You may also see a cooling curve, which is obtained when a substance cools down and changes state.
Changing state pt.2 and Specific latent heat
Notice that the temperature stays the same during a change of state, melting or boiling, even though heat energy is still being absorbed.
The temperature also stays the same while a liquid freezes, even though heat energy is still being released to the surroundings.
specific latent heat
The specific latent heat of a substance is a measure of how much heat energy is needed to melt or boil it. It is the energy needed to melt or boil 1 kg of the substance.
Different substances have different specific latent heats. The specific latent heat of a given substance is different for boiling than it is for melting. The table shows some examples.