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Mrs. Martinez Sixth Grade Rosemont Middle School

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1 Mrs. Martinez Sixth Grade Rosemont Middle School
Heat Transfer Mrs. Martinez Sixth Grade Rosemont Middle School

2 Welcoming Work Walking in the desert, Tom had to make a decision to either put on his white or black t-shirt. Which should he choose if the temperature is 100°? Why? Discuss answers with a partner

3 Welcoming Work What makes popcorn pop?
Describe the process that makes popcorn. Think of convection,radiation, and conduction.

4 You will 9A Investigate methods of thermal energy transfer, including conduction, convection, and radiation. 9B Verify through investigations that thermal energy moves in a predictable pattern from warmer to cooler until all the substances attain the same temperature such as an ice cube melting.

5 Vocabulary Law of Conservation of Energy Thermal energy Conduction
Convection Radiation Heat transfer

6 Heat Transfer Heat always moves from a warmer place to a cooler place.
Hot objects in a cooler room will cool to room temperature. Cold objects in a warmer room will heat up to room temperature.

7 Question If a cup of coffee and a red popsicle were left on the table in this room what would happen to them? Why? The cup of coffee will cool until it reaches room temperature. The popsicle will melt and then the liquid will warm to room temperature.

8 Rap introduction

9 Force, motion, and energy: Law of Conservation of Energy
The Law of Conservation of Energy states that energy can neither be created nor destroyed, it just changes form.

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11 16.1 Thermal Energy and Matter
Heat – transfer of thermal energy from one object to another because of temperature difference. Heat flows spontaneously from hot objects to cold objects.

12 The motion of molecules produces heat
Molecules and Motion The motion of molecules produces heat The more motion, the more heat is generated

13 The movement of heat from a warmer object to a colder one
Heat Transfer The movement of heat from a warmer object to a colder one

14 Three forms of heat transfer: Conduction Convection Radiation

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17 Conduction involves the transfer of heat through direct contact
Heat conductors conduct heat well, insulators do not

18 Conduction Conduction – heat transferred by particles colliding into one another, such as in a metal. Transfer of energy by touch Not an effective transfer in a gas. Primarily solids

19 Convection Convection – transfer of thermal energy when particles of a fluid move from one place to another

20 Takes place in liquids and gases as molecules move in currents
Convection Takes place in liquids and gases as molecules move in currents Heat rises and cold settles to the bottom

21 Convection Currents Convection currents – occur when a fluid circulates in a loop as it alternately heats up and cools down Important in many natural cycles such as ocean currents, weather systems, and movements of hot rock in Earth’s interior

22 Convection Convection – heat transferred by the circulation of a fluid (or gas), such as in a heating system at home; important near the surface of the Sun. Hot air rises cool air falls

23 What is this called?

24

25 Radiation – transfer of energy by waves moving through space
All objects radiate energy Rate at which energy radiates increases with temp.

26 Heat is transferred through space
Radiation Heat is transferred through space Energy from the sun being transferred to the Earth

27 Radiation Radiation – heat transferred by the flow of electromagnetic radiation, like heat felt from the campfire. Radiation is the only type of heat transfer that can happen in a vacuum. Heat transfer through waves

28 Heat Transfer CONDUCTION: the transfer of energy through matter
by direct contact of particles. This can happen in solids, liquids and gases. CONVECTION: the transfer of energy because of the movement of bulk masses of particles. This can happen only in liquids and gases - not in solids. RADIATION: the transfer of energy by electromagnetic waves. Energy can move by radiation in air like the heat from your electric stove top, or in the vacuum of space the way the Sun heats the Earth. In radiation, the energy does not have to transfer through mass (particles).

29 What are the three types of heat transfer?
Questions What are the three types of heat transfer? How is conduction different from radiation?

30 What type of heat transfer is involved?
Heating a room with a fireplace Egg cooking in a frying pan Roof of a house becoming hot

31 What type of heat transfer?
Warm air mass bringing a change in the weather Wire getting hot from an electric appliance

32 How is kinetic energy related to heat production?
Question How is kinetic energy related to heat production?

33 Thermometer A instrument used to measure temperature
Thermometers commonly have alcohol (with dye) or mercury Digital thermometers have replaced older ones

34 The expansion of a substance due to heat
Heat expansion The expansion of a substance due to heat Most solids, liquids, and gases expand as they are heated

35 Just in Case you missed the Vocabulary
conduction: the transfer of heat through a material by direct contact. convection: the transfer of heat in a fluid (gas or liquid) as a result of the movement of the fluid itself. radiation: the transfer of heat via electromagnetic waves through space. heat transfer: the transfer of thermal energy between substances due to a difference in their temperatures.

36 Heat Vent

37 Heat Transfer Experiment

38 From the sun:

39 Metal Rod

40 68. In which container is the substance unable to transfer heat by
68 In which container is the substance unable to transfer heat by convection? F H G J

41  Problem 11 In which container is the substance unable to
transfer heat by convection?

42 Air Currents are what type of heat transfer?

43 Heat cells in mantle/asthenosphere Rising heat cells - plates separate
Heat cells in mantle/asthenosphere Rising heat cells - plates separate Sinking heat cells - plates pulled down into mantle

44 The Sun

45 heat transfer : Problem 10
Heat convection occurs in gases and liquids. Heat convection does not occur in solids because solids are unable to — A absorb heat by vibrating B transfer heat by fluid motion C emit radiation by reflecting light D exchange heat by direct contact

46 Each finger is a different metal rod with glass marbles affixed using wax. The marbles are placed at equal distances on each of the rods and the rods are heated. The heat is moved through the metal to the wax adhesive. As the wax warms up, it looses its stickiness and the marbles subsequently fall off.

47 Problem 12 The moon’s surface becomes hot during the long lunar day because the sun transfers heat to the moon. This heat transfer is accomplished almost entirely through the process of — F convection G refraction H conduction J radiation

48 Problem 13 A man who was sleeping wakes up because he hears the smoke alarm go off in his house. Before opening the bedroom door, the man feels the door to see whether it is warm. He is assuming that heat would be transferred through the door by — A conduction B convection C radiation D compression

49 Problem 14 The transfer of heat by the movement of air currents in Earth’s atmosphere is an example of — A conduction B convection C radiation D fusion

50 Heat Lamps

51 65 Heat convection occurs in gases and liquids
65 Heat convection occurs in gases and liquids. Heat convection does not occur in solids because solids are unable to — A absorb heat by vibrating B transfer heat by fluid motion C emit radiation by reflecting light D exchange heat by direct contact

52 Temperatures of Water in
69 Container P and Container Q each were filled with 0.5 liter of water. The water was heated to 90°C. The table shows the temperatures after both containers were allowed to cool for 3 minutes. Compared to Container Q, Container P is a better — A conductor B absorber C radiator D insulator Temperatures of Water in Different Containers Container Initial Temperature (°C) Final P 90 83 Q 76

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