activator: why is the sun important? how does the heat get from this big, bright, ball in the sky to...

Activator: •Why is the sun important?•How does the heat get from this big, bright, ball in the sky to us?

Temperature and thermal energy

Things to think about:Temperature – measure of the average kinetic energy of the particles in an object (noun)

Thermal energy – the TOTAL energy of the particles that make an object (noun)

Heat – the transfer of energy between objects at different temperatures (verb)

1)Temperature is a measure of the average kinetic energy of the particles in an object

2)The more kinetic energy particles have the higher the temperature will be

3) Temperature (unlike thermal energy) is not determined by the amount of substance. BUT – if you have more of the substance you will have MORE thermal energy because you have more particles

4) Thermal expansion is the increase in volume of a substance due to an increase in temperature (average kinetic energy).

Particles spread away from each other when heated

When particles spread apart the substance becomes less dense.

5) The three temperature scales we use are:FahrenheitWater Freezes = Water Boils = CelsiusWater Freezes = Water Boils = KelvinWater Freezes = Water Boils =

The lowest possible temperature on the Kelvin scale, and all particle

motion stops.

We have never achieved this temperature, only come close.

Section 2: Heat

1) Heat is the transfer of thermal energy between objects that are at different temperatures.

2) Thermal Energy is the TOTAL energy of particles that make up a substance.

It depends on temperature and amount of the substance.

3) The three ways thermal energy is transferred:

ConductionConvectionRadiation

4) Conduction is the transfer of thermal energy through direct contact between objects

5) Items that transfer thermal energy well are called conductors (metals)

Items that DO NOT conduct energy well are called insulators

Every atom is physically bonded to its neighbors in some way. If heat energy is supplied to one part of a solid, the atoms vibrate faster. As they vibrate more, the bonds between atoms are shaken more. This passes vibrations on to the next atom, and so on:            Eventually the energy spreads throughout the solid.

The overall temperature has increased.

6) Convection: transfer of thermal energy by movement in a liquid or gas, through currents. Cool stuff sinks Warm stuff rises

7) Radiation is the transfer of thermal energy through matter or space as electromagnetic waves.

Examples: light and heat from a fire

1) Temperature is based on the movement of particles in an object, but thermal energy is based on the total amount of particles in that object.

2) Thermal energy is based on the total amount of particles in that object, but heat is the transfer of thermal energy between two objects.

Fill in the tree map to describe the difference between these three terms.

Kinetic theory of matter

Thermal energy temperature heat

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