THERMAL ENERGY AND HEAT Jennefer Cardenas

Objectives Students will be able to identify and know difference between THERMAL ENERGY, TEMPERATURE, and HEAT. Students will be able to identify the 3 ways heat is transferred. Students will be able to compare different conductors and insulators. Students will be able to compare Celsius and Fahrenheit Scale.

TEMPERATURE The measure of the average kinetic energy of the individual particles in an object. Matter is made up of tiny particles called atoms and molecules. These particles are always in motion even if the object they make up isn’t moving at all. Energy of motion is called kinetic energy, so all particles of matter have kinetic energy. The faster the particles are moving, the more kinetic energy they have.

WATER AND DYE EXPERIMENT Why did the dye in hot water move faster than the dye in cold water? The results have to do with the different temperatures of the water.

Back to Experiment So what explanation would be given if we heated the cold water.  Its particles will start moving faster, so their kinetic energy will increase. This means that the temperature of the water will rise.

THERMAL ENERGY The total energy of all the particles. If 2 samples of matter are at the same temperature they do not necessarily have the same total energy.

What is Heat ? How is heat transferred? Heat is thermal energy moving from a warmer object to a cooler object. There are 3 ways that heat can move.  Conduction  Convection  Radiation

CONDUCTION Heat conduction or thermal conduction is the transfer of thermal energy through matter, from a region of higher temperature to a region of lower temperature, and acts to equalize temperature differences. It is also described as heat energy transferred from one material to another by direct contact.

CONVECTION Convection is the movement of molecules within fluids ( a liquid or a gas); the warm fluid rises and cooler fluids flow in to replace it. This creates a circular flow.

More Convection The wind we feel outside is often the result of convection currents. You can understand this by the winds you feel near an ocean. Warm air is lighter than cold air and so it rises. During the daytime, cool air over water moves to replace the air rising up as the land warms the air over it. During the nighttime, the directions change -- the surface of the water is sometimes warmer and the land is cooler.

RADIATION The transfer of energy by electromagnetic waves. Radiation does not require matter to transfer thermal energy.

Radiation The sun's rays travel in straight lines called heat rays. When it moves that way, it is called radiation. When sunlight hits the earth, its radiation is absorbed or reflected.

Conductors and insulators A conductor is an object that can conduct heat well An insulator is an object that conducts heat poorly.

ASSESMENT What are the 3 ways heat is transferred Convection, Conduction, and Radiation TRUE or FALSE The transfer of energy by electromagnetic waves is the definition for Convection False TRUE or FALSE In this picture “B” is representing a heat conductor and “A” is representing heat convection? True