Heat  A Form of   Energy
Molecules and Motion• The motion of  molecules produces  heat• The more motion, the  more heat is generated
Heat Transfer• The movement of heat  from a warmer object  to a colder one
Forms of heat transfer• Three forms of heat  transfer:• Conduction• Convection• Radiation
Conduction• Conduction involves  the transfer of heat  through direct contact• Heat conductors  conduct heat well,  insula...
Convection• Takes place in liquids and  gases as molecules move  in currents• Heat rises and cold  settles to the bottom
Radiation• Heat is transferred  through space• Energy from the sun  being transferred to the  Earth
Questions• What are the three types of heat  transfer?• How is conduction different  from radiation?
What type of heat transfer is          involved?• Heating a room with a  fireplace• Egg cooking in a frying  pan• Roof of ...
What type of heat         transfer?• Warm air mass bringing  a change in the  weather• Wire getting hot from  an electric ...
Temperature and Heat• Kinetic energy is the  energy of motion• Temperature is the  measure of the average  kinetic energy ...
Question• How is kinetic energy  related to heat  production?
Thermometer• A instrument used to measure  temperature• Thermometers commonly have  alcohol (with dye) or mercury• Digital...
Celsius Scale• Celsius is the metric  scale for measuring  temperature• Water freezes at 0ºC  and boils at 100ºC
Kelvin scale• The Kelvin scale is a  metric temperature scale  measured in Kelvin units  (K)• Formula (273+ºC)= Kelvin
Questions• What is the formula for converting a  Celsius temperature to a Kelvin  temperature?• What is the boiling point ...
Absolute zero• The temperature in  which all molecular  motion stops (0 K)
Questions• Describe absolute zero.• What is absolute zero  on the Celsius scale?
Measuring Heat• Increase in temperature• Addition of heat• A decrease in  temperature• Removal of heat
Calories• Unit for measuring heat• The amount of heat  needed to raise 1 gram  of water one degree  Celsius
Temperature• Joule is another unit for  measuring heat• Mass and type of  substance determine  the amount of  temperature ...
Specific Heat• The ability of a substance to  absorb heat energy (specific heat)• Different substances absorb heat  at dif...
What is a calorimeter?• Device used to  measure the heat given  off during chemical  reactions
Questions• How can heat be  measured?• What is the unit used  to measure heat?• What is specific heat?
Heat and Phase       Changes• A phase change is a  physical change that  requires a change in heat  energy• Addition or re...
Questions• What is freezing point,  melting point, and  boiling point?
Heat expansion• The expansion of a  substance due to heat• Most solids, liquids,  and gases expand as  they are heated
Expansion of water• Between 4ºC and 0ºC,  water EXPANDS as it  cools and turns into a  solid
Thermostat• A thermostat is a  device that controls  the temperature• The switch of a  thermostat is a  bimetallic strip
Bimetallic Strip• Two different metals that are  bound together• They expand at different rates  when heated• Used as a sw...
Internal energy• The energy within a  substance
Questions• What is internal energy?• What is a thermostat?• Describe the switch of a  thermostat.• What happens to most  s...
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Heat

  1. 1. Heat A Form of Energy
  2. 2. Molecules and Motion• The motion of molecules produces heat• The more motion, the more heat is generated
  3. 3. Heat Transfer• The movement of heat from a warmer object to a colder one
  4. 4. Forms of heat transfer• Three forms of heat transfer:• Conduction• Convection• Radiation
  5. 5. Conduction• Conduction involves the transfer of heat through direct contact• Heat conductors conduct heat well, insulators do not
  6. 6. Convection• Takes place in liquids and gases as molecules move in currents• Heat rises and cold settles to the bottom
  7. 7. Radiation• Heat is transferred through space• Energy from the sun being transferred to the Earth
  8. 8. Questions• What are the three types of heat transfer?• How is conduction different from radiation?
  9. 9. 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
  10. 10. What type of heat transfer?• Warm air mass bringing a change in the weather• Wire getting hot from an electric appliance
  11. 11. Temperature and Heat• Kinetic energy is the energy of motion• Temperature is the measure of the average kinetic energy of an object
  12. 12. Question• How is kinetic energy related to heat production?
  13. 13. Thermometer• A instrument used to measure temperature• Thermometers commonly have alcohol (with dye) or mercury• Digital thermometers have replaced older ones
  14. 14. Celsius Scale• Celsius is the metric scale for measuring temperature• Water freezes at 0ºC and boils at 100ºC
  15. 15. Kelvin scale• The Kelvin scale is a metric temperature scale measured in Kelvin units (K)• Formula (273+ºC)= Kelvin
  16. 16. Questions• What is the formula for converting a Celsius temperature to a Kelvin temperature?• What is the boiling point of water on the Kelvin scale?• What is the freezing point of water on the Kelvin scale?
  17. 17. Absolute zero• The temperature in which all molecular motion stops (0 K)
  18. 18. Questions• Describe absolute zero.• What is absolute zero on the Celsius scale?
  19. 19. Measuring Heat• Increase in temperature• Addition of heat• A decrease in temperature• Removal of heat
  20. 20. Calories• Unit for measuring heat• The amount of heat needed to raise 1 gram of water one degree Celsius
  21. 21. Temperature• Joule is another unit for measuring heat• Mass and type of substance determine the amount of temperature change
  22. 22. Specific Heat• The ability of a substance to absorb heat energy (specific heat)• Different substances absorb heat at different rates• The greater the mass of the object the more heat is absorbed
  23. 23. What is a calorimeter?• Device used to measure the heat given off during chemical reactions
  24. 24. Questions• How can heat be measured?• What is the unit used to measure heat?• What is specific heat?
  25. 25. Heat and Phase Changes• A phase change is a physical change that requires a change in heat energy• Addition or removal of HEAT
  26. 26. Questions• What is freezing point, melting point, and boiling point?
  27. 27. Heat expansion• The expansion of a substance due to heat• Most solids, liquids, and gases expand as they are heated
  28. 28. Expansion of water• Between 4ºC and 0ºC, water EXPANDS as it cools and turns into a solid
  29. 29. Thermostat• A thermostat is a device that controls the temperature• The switch of a thermostat is a bimetallic strip
  30. 30. Bimetallic Strip• Two different metals that are bound together• They expand at different rates when heated• Used as a switch in a thermostat
  31. 31. Internal energy• The energy within a substance
  32. 32. Questions• What is internal energy?• What is a thermostat?• Describe the switch of a thermostat.• What happens to most substances when heat is added?

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