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Heat and temperature CONTENTS RESOURCES.

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Presentation on theme: "Heat and temperature CONTENTS RESOURCES."— Presentation transcript:

1 Heat and temperature CONTENTS RESOURCES

2 CONTENTS Heat and temperature Heat Definition Measurement Temperature
Temperature and mearurement Thermometers Temperature scales Effects of heat Effects on matter Expansion and contraction Changes of state Heat transfer Conduction Conductors and insulators Convection Radiation

3 RESOURCES Heat Heat measurement Temperature and measurement
Thermometers Temperature scales Effects of heat Expansion and contraction Changes of state Conduction Conductors and insulators Links Heat and temperature Convection Radiation

4 Heat is energy in transit.
Heat is the amount of thermal energy that is transferred from one body or system to another, due to a difference in temperature. SEE ANIMATION

5 Heat is energy in transit.
Heat is the amount of thermal energy that is transferred from one body or system to another, due to a difference in temperature. Heat flow stops when their temperatures are the same, that is, thermal equilibirum. Heat flows from the hot iron rod to the cold water. GO BACK

6 Units of heat: joules (J) calories (cal)
Heat measurement Heat is measured in units of joules or calories. heat Units of heat: joules (J) calories (cal) 1 J = 0.24 cal 1 cal = J

7 Temperature and measurement
Temperature is the amount of heat in a system. Temperature can be measured with a thermometer.

8 X X Thermometers Alcohol thermometer
They are used to measure atmospheric temperature. X [close] Alcohol thermometer coloured alcohol They are used to measure body temperature. X [close] Clinical thermometer mercury

9 Temperature scales water ºF ºC K Fahrenheit scale (ºF)
Celsius scale (ºC) Kelvin or absolute scale (K) 100 80 60 40 20 373 353 333 313 293 273 Boiling point 212 176 140 104 68 Freezing point 32 water

10 Effects of heat Heat produces the following effects on matter: Expansion Contraction

11 Heat produces the following effects on matter:
Effects of heat Heat produces the following effects on matter: Expansion: The increase in volume which occurs when a system gains heat. Expansion Contraction

12 Heat produces the following effects on matter:
Effects of heat Heat produces the following effects on matter: Contraction: the decrease in volume which occurs when a system loses heat. Expansion Contraction

13 Expansion and contraction
Solids Liquids Gases The gas inside a balloon expands when heated. Mercury expands when heated. Expansion joints expand when it is hot. WHAT HAPPENS WHEN RAILS CONTRACT? WHAT HAPPENS WHEN A GAS EXPANDS? The particles are not free to move. Solids do not expand much. The particles move more freely than in solids. Liquids usually expand more than soilds. The particles are far apart and move more freely than in liquids. Gases usually expand more than liquids.

14 X Expansion and contraction Solids Liquids The rails cool. Gases
The gas inside a balloon expands when heated. X [close] Mercury expands when heated. Expansion joints expand when it is hot. 10 The particles move more slowly and occupy less space. WHAT HAPPENS WHEN A GAS EXPANDS? 10 The volume decreases, and the rails contract. The particles are not free to move. Solids do not expand much. The particles move more freely than in solids. Liquids usually expand more than soilds. The particles are far apart and move more freely than in liquids. Gases usually expand more than liquids.

15 X Expansion and contraction
Gases X [close] Solids Liquids Gases The gas inside a balloon expands when heated. Mercury expands when heated. Expansion joints expand when it is hot. When gas expands, the volume increases. This can push a cork out. WHAT HAPPENS WHEN RAILS CONTRACT? The particles are not free to move. Solids do not expand much. The particles move more freely than in solids. Liquids usually expand more than soilds. The particles are far apart and move more freely than in liquids. Gases usually expand more than liquids.

16 When a state of matter gains or loses heat, it undergoes
Changes of state SOLID LIQUID GAS melting solidifcation sublimation desublimation evaporation condensation endothermic exothermic Heat changes can be: When a state of matter gains or loses heat, it undergoes a change.

17 This is the transfer of heat in most solids.
Conduction This is the transfer of heat in most solids. particles of a solid The kinetic energy of the particles increases. Direction of heat Heat is transferred by direct contact.

18 Conductors and insulators
metal Conductors allow heat to move through them easily. plastic Double-glazed window air air space cork Insulators do not allow heat to move through them easily.

19 This is the transfer of heat in liquids and gases.
Convection This is the transfer of heat in liquids and gases. gas particles convection currents liquid particles Heat is transferred by the movement of currents.

20 This is the transfer of heat by electromagnetic waves.
Radiation This is the transfer of heat by electromagnetic waves. radiation emitted by plants solar radiation Greenhouse No contact is necessary between the source and the heated substance.

21 Links Heat Heat and temperature Transfer of thermal energy
Heat Transfer of thermal energy Solids, liquids and gases and the particle theory Heat transfer activities Thermodynamics How is heat transferred Hands-on physics: Heat & temperature


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