Heat energy is due to the movement of atoms or molecules. As atoms move faster they create more energy = causing Heat!

 Depends upon the mass, temperature and phase of an object.

 Expansion occurs:  1. Particles move faster  2. Particles collide and bounce  3. The substance EXPANDS  Volume Expansion: Liquids take up more space than solids when heated.  Linear Expansion: Solids get longer as they are heated.

 A material through which Heat can be easily transferred.  Examples: Most metals

 A material that is a poor conductor of heat or energy. Gases, liquids make good insulators  Examples: Plastics (polypropylene), wood, wool, Insulation.

 The transfer of heat energy by the movements of fluids or air at different temperatures.  Examples: Heating a room, Ocean currents, wind

 The flow of a fluid due to heated expansion, followed by cooling and contraction. Occurs in Water only  Example: Gulf stream, Boiling Pot of pasta

 The transfer of energy as heat between particles as they collide in a substance or The transfer of energy as heat by CONTACT or touch.  Heat always transfers from the hotter object to the colder one.  Examples: placing metal rod in a fire

 The transfer of heat energy by electromagnetic waves (LIGHT).  Examples: The sun warming the earth, standing by a fire

 Definition – The measure of the average kinetic energy of the molecules in an object.

 A tool that measures temperature – measures the amount of heat present.

 Fahrenheit: Water freezes at 32°F  water Boils at 212°F  Body Temp. 100°F  Conversion from F to C C = 5/9 x (F-32)

 Celsius : Water freezes at 0°C Water Boils at 100°C Body Temp. 37°C Conversion from F to C F = (9/5 x C) + 32

 Kelvin Scale = used to measure very low or very high temperatures  Absolute Zero = Temperature at which molecules stop moving O K

 Liquid in the thermometer  (either mercury or alcohol) expands and contracts due to the heat present.  Why isn’t water used in thermometers?

 As objects cool down the molecules in them move more slowly producing less kinetic energy (HEAT), so the objects CONTRACT.

 Bimetallic Strip: 2 different metals are fused together, one expands faster than the other when heated. As the strip is heated it curls or bends due to the metals.  Bimetallic strips are used in Thermostats to turn them off and on as the metals expand and contract due to heat.

 Safety devices that turn off electricity if circuit gets too hot.

 Heat energy can come from chemical reactions.  Exothermic Reaction – Heat is released -Feels hot  Endothermic Reaction – heat is absorbed – feels cold