Science Study Notes Heat and Temperature Unit C Grade 7
Part A)
1. Theories of heat
Caloric theory of heat- Heat energy was a substance (like a liquid or an invisible fluid) which flowed from a hot object to a colder one. But there is one weakness for this theory; why doesn’t the mass of the objects change if the ‘substances’ are flowing in and out of the objects. If the caloric theory of heat was real, the mass of the objects would change.
Heat as energy theory-
Heat was a form of energy and was related to the movement of the particles in an object. The faster the particles move, the more heat energy an object had.
2. States of Matter-
All matter is made up of extremely tiny particles.
The tiny particles of matter are always moving.
Adding heat to the matter makes the particles move around faster.
The particles have space between them.
Particle Model-
Solid to liquid- melting ; heat is increasing
Liquid to gas- boiling; heat is increasing
Gas to liquid- condensation; heat is decreasing
Liquid to solid- freezing; heat is decreasing
3. Temperature and Heat
Kinetic Energy- energy of movement; particles that make up matter have Ek.
Thermal Energy- total Ek of all the particles the substance contains
Temperature- the average amount of Ek
4. Expansion and Contraction
When heat is added to a substance it vibrates faster, moves farther apart, therefore making the substance increase in volume/size.
When heat is removed from a substance it vibrates slower, moves closer together, therefore making the substance decrease in volume/size.
5. Conduction and Insulation
Conductors- transfers heat effectively (heat transfers in only one direction; from greater areas of Ek to areas of less Ek.
Insulators- do not conduct heat well; resist the flow of heat
6. Convection
Convection- In convection, heat is transferred when liquid or gas moves from one area to another.
* In conduction, only the heat moves, not the particles; but in convection, not only does the heat move, the particles move with the heat as well.
7. R-value and Thermogram
R-value-
