• Is the measure of the average kinetic energy of the particles in a substance

• As the particles in a substance move faster and their kinetic energy becomes greater, the temperature of a substance rises.

• Temperature is measured using a thermometer.

Temperature

• Thermal or internal energy – the total energy of the particles in a substance (both kinetic and potential energies)

• Heat – thermal energy flowing from hot to cold areas.

• Measured in Joules or Calories

Heat Energy

• Objects with slower moving particles have LOW heat energy

• Objects with faster moving particles have HIGH heat energy

Heat Energy

Which has more heat energy?

How is that possible?

Heat is the total energy of the particles in the material.

The iceberg is colder , but it has way more particles!

There are 3 temperature scales

•The transfer of energy by direct contact of particles.

•Heat energy is transferred by molecules colliding with one another

•Heat energy is transferred by moving fluids (liquids or gases).

•Hotter particles are less dense, so they rise, and cooler particles are more dense, so they sink.

• This creates a convection current of air or water flowing up and then back down as it warms up and cools off repeatedly

The movement of particles forms convection currents.

Heat Transfers

Problem Solving

While working at a restaurant, John was clearing the table where 2 customers had been sitting. One had a cup of hot chocolate and the other had a cold soda. When he picked up the remaining portions of their drinks he noticed that both the hot chocolate and the cold soda were now both at the same temperature.

1.Describe what took place to bring both liquids to room temperature.

2.Where does the heat lost by the hot chocolate go?

3.If heat flows in only one direction, how can both hot and cold liquids reach room temperature?