Temperature and Heat Transfer

Food and Cooking UnitMrs. Caldwell’s Class

Temperature

• Temperature is the measure of the kinetic energy of all particles in an object. • Remember that kinetic energy is the

energy of motion and that all atoms are constantly in motion.

Examples of Temperature• If a liquid has a high temperature, the particles

in the liquid are moving fast and have high average kinetic energy.

• If a liquid has a low temperature the particles in the liquid are moving more slowly and have a low average kinetic energy.

High Average Kinetic Energy = High Temperature

Low Average Kinetic Energy = Low Temperature

Measuring Temperature

• Temperature is measured in degrees.• The temperature scale used in science is the

Celsius scale. • Water freezes at 0 degrees Celsius.• Water boils at 100 degrees Celsius.• A thermometer is used to measure

temperature.

Heat – the flow of energy from an object at a warmer temperature to an object at a cooler temperature.

The Transfer of Heat Energy

• Conduction – the process that moves energy from one object to another when they are touching physically.

• Conductors – materials that transfer energy easily. –Example: Metals

• Insulators – poor conductors. –Example: Foam Cup

• Convection – the process that transfers energy by the movement of large numbers of particle in the same direction within a liquid or a gas. – Example: warm and cold air in the atmosphere.

The Transfer of Heat Energy

The Transfer of Heat Energy

• Radiation – energy that ravels as electromagnetic waves, which include visible light, microwaves and infrared light. – Example: Microwave Oven

Questions1. What is temperature?2. What happens when a liquid is hot? Cold?3. How is heat transfer demonstrated when you

cook?4. Will cold or hot water boil first? 5. What are the three ways that heat energy is

transferred?6. Name one example of a conductor and one

example of an insulator.