Heat and temperature

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Heat and temperature

  1. 1. Heat and Temperature Heat and temperature are often confused. They are very different concepts.
  2. 2. Heat and TemperatureThere are actually threeconcepts that need to bedistinguished: Heat Temperature Thermal energy
  3. 3. Heat and Temperature Heat is the energy transferred from one object to another because of a difference in temperature.Heat energy always flows from a hotter object to a colder object.
  4. 4. Heat and TemperatureThermal energy is thesum total of the energyof all the molecules inan object.Thermal energy all the energy in a single object Heat energy transferred between two objects
  5. 5. Heat and Temperature Temperature measures the average energy of motion of the molecules in an object.Fast moving molecules hot object (high temperature)Slow moving molecules cold object (low temperature)
  6. 6. Heat and TemperatureNow test yourunderstanding withthis three-questionquiz!
  7. 7. True or false? An iceberg has morethermal energy than a cup of coffee. True False
  8. 8. True or false? An iceberg has more thermal energy than a cup of coffee. This is true – you are correct The individual iceberg molecules have much less energy than theindividual coffee molecules. But the total energy of the iceberg isgreater because it has so many more molecules. Go to question 2
  9. 9. True or false? An iceberg has more thermal energy than a cup of coffee. Sorry – false is incorrect The individual iceberg molecules have much less energy than theindividual coffee molecules. But the total energy of the iceberg isgreater because it has so many more molecules. Go to question 2
  10. 10. A 1 litre saucepan and a 2 litresaucepan are both filled withwater, placed on identical stoveelements, and heated. After oneminute: A. Both pans have received the same amount of heat and both are at the same temperature. B. Both pans are at the same temperature but the 2 litre pan has received more heat. C. Both pans have received the same amount of heat but the 1 litre pan is hotter.
  11. 11. A 1 litre saucepan and a 2 litresaucepan, are both filled withwater, placed on identical stoveelements, and heated. After oneminute: Sorry, option A is incorrect  Both pans receive the same amount of heat as they are on identical elements. But the 1 litre pan is hotter because it has half as many molecules. In fact its temperature increase is double that of the 2 litre pan. Go to question 3
  12. 12. A 1 litre saucepan and a 2 litresaucepan are both filled withwater, placed on identical stoveelements, and heated. After oneminute: Sorry, option B is incorrect  Both pans receive the same amount of heat as they are on identical elements. But the 1 litre pan is hotter because it has half as many molecules. In fact its temperature increases by double that of the 2 litre pan. Go to question 3
  13. 13. A 1 litre saucepan and a 2 litresaucepan are both filled withwater, placed on identical stoveelements, and heated. After oneminute: Yes, option C is correct – well done  Both pans receive the same amount of heat as they are on identical elements. But the 1 litre pan is hotter because it has half as many molecules. In fact its temperature increases by double that of the 2 litre pan. Go to question 3
  14. 14. 1 kg of water and a 1 kg iron pan areidentically heated. After one minute:A. Both the water and the iron pan are at thesame temperature.B. The water is hotter than the pan.C. The pan is hotter than the water.
  15. 15. 1 kg of water and a 1 kg iron pan areidentically heated. After one minute: Sorry, option A is incorrect  Because of its molecular structure, iron gets hotter quicker than water when the same amount of heat is supplied. That is why pans quickly become ‘red hot’ on the stove if there is no liquid to absorb the heat.
  16. 16. 1 kg of water and a 1 kg iron pan areidentically heated. After one minute: Sorry, option B is incorrect  Because of its molecular structure, iron gets hotter quicker than water when the same amount of heat is supplied. That is why pans quickly become ‘red hot’ on the stove if there is no liquid to absorb the heat.
  17. 17. 1 kg of water and a 1 kg iron pan areidentically heated. After one minute: Yes, option C is correct – well done  Because of its molecular structure, iron gets hotter quicker than water when the same amount of heat is supplied. That is why pans quickly become ‘red hot’ on the stove if there is no liquid to absorb the heat.

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