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

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Presentation on theme: "Heat energy is due to the movement of atoms or molecules. As atoms move faster they create more energy = causing Heat!"— Presentation transcript:

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

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

4  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.

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

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

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

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9  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

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11  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

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

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

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

17  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)

18  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

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

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

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

22  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.

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

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


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