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Why do we use water in a hot water bottle rather than sand or a metal lump to warm up a bed?

Specific heat capacity ‘c’. Why do we use water in a hot water bottle rather than sand or a metal lump to warm up a bed?. Specific heat capacity ‘c’. Why is our sea water always cold in the UK, where as the land heats up and cools down quickly?.

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Why do we use water in a hot water bottle rather than sand or a metal lump to warm up a bed?

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  1. Specific heat capacity ‘c’ Why do we use water in a hot water bottle rather than sand or a metal lump to warm up a bed?

  2. Specific heat capacity ‘c’ Why is our sea water always cold in the UK, where as the land heats up and cools down quickly?

  3. Specific heat capacity ‘c’ • The amount of energy an object can store depends on: • i) the material it’s made from • its mass • how hot it is Specific heat capacity ‘c’ is the energy needed to increase the temperature of 1Kg of the substance by 1 0 C . Units of ‘c’ are J/kg/ 0 C Energy transferred = mass x sp. ht. cap. x temperature change E = m x c x θ Degrees Celsius 0C Joules, J Kilograms, kg Sp.ht.cap, J / kg / 0 C

  4. Specific heat capacity ‘c’ • The amount of energy an object can store depends on: • i) the material it’s made from • its mass • how hot it is Specific heat capacity ‘c’ is the energy needed to increase the temperature of 1Kg of the substance by 1 0 C . Units of ‘c’ are J/kg/ 0 C Energy transferred = mass x sp. ht. cap. x temperature change E = m x c x θ Degrees Celsius 0C Joules, J Kilograms, kg Sp.ht.cap, J / kg / 0 C

  5. Specific heat capacity ‘c’ • The amount of energy an object can store depends on: • i) the material it’s made from • its mass • how hot it is Specific heat capacity ‘c’ is the energy needed to increase the temperature of 1Kg of the substance by 1 0 C . Units of ‘c’ are J/kg/ 0 C Energy transferred = mass x sp. ht. cap. x temperature change E = m x c x θ Degrees Celsius 0C Joules, J Kilograms, kg Sp.ht.cap, J / kg / 0 C

  6. Specific heat capacity ‘c’ • The amount of energy an object can store depends on: • i) the material it’s made from • its mass • how hot it is Specific heat capacity ‘c’ is the energy needed to increase the temperature of 1Kg of the substance by 1 0 C . Units of ‘c’ are J/kg/ 0 C Energy transferred = mass x sp. ht. cap. x temperature change E = m x c x θ Degrees Celsius 0C Joules, J Kilograms, kg Sp.ht.cap, J / kg / 0 C

  7. Experiment to compare the energy needed to raise the temperature by 5 oC for 1kg aluminium and 1kg water 36 W heater t1 = …. t2 = …. 1kg t1 = …. t2 = …. 1kg Conclusions: Water has a higher sp. ht. cap. than aluminium. Uncertainties are caused by errors in the readings and heat loss. Energy = power x time Energy = power x time E = 36 x …. s E = 36 x …. s E = …. Joules E = …. Joules

  8. Time taken ……….. s Time taken ……….. s Experiment to compare the energy needed to raise the temperature by 5 oC for 1kg aluminium and 1kg water 36 W heater t1 = …. t2 = …. 1kg t1 = …. t2 = …. 1kg Conclusions: Water has a higher sp. ht. cap. than aluminium. Uncertainties are caused by errors in the readings and heat loss. Energy = power x time Energy = power x time E = 36 x …. s E = 36 x …. s E = …. Joules E = …. Joules

  9. Time taken ……….. s Time taken ……….. s Experiment to compare the energy needed to raise the temperature by 5 oC for 1kg aluminium and 1kg water 36 W heater t1 = …. t2 = …. 1kg t1 = …. t2 = …. 1kg Conclusions: Water has a higher sp. ht. cap. than aluminium. Uncertainties are caused by errors in the readings and heat loss. Energy = power x time Energy = power x time E = 36 x …. s E = 36 x …. s E = …. Joules E = …. Joules

  10. Time taken ……….. s Time taken ……….. s Experiment to compare the energy needed to raise the temperature by 5 oC for 1kg aluminium and 1kg water 36 W heater t1 = …. t2 = …. 1kg t1 = …. t2 = …. 1kg Conclusions: Water has a higher sp. ht. cap. than aluminium. Uncertainties are caused by errors in the readings and heat loss. Energy = power x time Energy = power x time E = 36 x …. s E = 36 x …. s E = …. Joules E = …. Joules

  11. Time taken ……….. s Time taken ……….. s Experiment to compare the energy needed to raise the temperature by 5 oC for 1kg aluminium and 1kg water 36 W heater t1 = …. t2 = …. 1kg t1 = …. t2 = …. 1kg Conclusions: Energy = power x time Energy = power x time E = 36 x …. s E = 36 x …. s E = …. Joules E = …. Joules

  12. Time taken ……….. s Time taken ……….. s Experiment to compare the energy needed to raise the temperature by 5 oC for 1kg aluminium and 1kg water 36 W heater t1 = …. t2 = …. 1kg t1 = …. t2 = …. 1kg Conclusions: Water has a higher sp. ht. cap. than aluminium. Uncertainties are caused by errors in the readings and heat loss. Energy = power x time Energy = power x time E = 36 x …. s E = 36 x …. s E = …. Joules E = …. Joules

  13. Specific heat capacity ‘c’ B grade: calculation: Calculate the energy required to raise 2 kg of the substances below a) Aluminium 880 J/kg/ 0 C from room temperature at 20 0C to 80 0C’. b) Copper 380 J/kg/ 0 C from 0 0C to 100 0C c) Oil 1200 J/kg/ 0 C from room temperature at 20 0C to 140 0C’. Energy transferred = mass x sp. ht. cap. x temperature change E = m x c x θ a) E = 2 x 880 x (80 – 20) E = 2 x 880 x 60 E = 105,600 J = 105.6 kJ

  14. Specific heat capacity ‘c’ B grade: calculation: Calculate the energy required to raise 2 kg of the substances below a) Aluminium 880 J/kg/ 0 C from room temperature at 20 0C to 80 0C’. b) Copper 380 J/kg/ 0 C from 0 0C to 100 0C c) Oil 1200 J/kg/ 0 C from room temperature at 20 0C to 140 0C’. Energy transferred = mass x sp. ht. cap. x temperature change E = m x c x θ a) E = 2 x 880 x (80 – 20) E = 2 x 880 x 60 E = 105,600 J = 105.6 kJ

  15. Specific heat capacity ‘c’ B grade: calculation: Calculate the energy required to raise 2 kg of the substances below a) Aluminium 880 J/kg/ 0 C from room temperature at 20 0C to 80 0C’. b) Copper 380 J/kg/ 0 C from 0 0C to 100 0C c) Oil 1200 J/kg/ 0 C from room temperature at 20 0C to 140 0C’. Energy transferred = mass x sp. ht. cap. x temperature change E = m x c x θ b) E = 2 x 380 x (100 – 0) E = 2 x 380 x 100 E = 76,600 J = 76.6 kJ

  16. Specific heat capacity ‘c’ B grade: calculation: Calculate the energy required to raise 2 kg of the substances below a) Aluminium 880 J/kg/ 0 C from room temperature at 20 0C to 80 0C’. b) Copper 380 J/kg/ 0 C from 0 0C to 100 0C c) Oil 1200 J/kg/ 0 C from room temperature at 20 0C to 140 0C’. Energy transferred = mass x sp. ht. cap. x temperature change E = m x c x θ b) E = 2 x 380 x (100 – 0) E = 2 x 380 x 100 E = 76,600 J = 76.6 kJ

  17. Specific heat capacity ‘c’ B grade: calculation: Calculate the energy required to raise 2 kg of the substances below a) Aluminium 880 J/kg/ 0 C from room temperature at 20 0C to 80 0C’. b) Copper 380 J/kg/ 0 C from 0 0C to 100 0C c) Oil 1200 J/kg/ 0 C from room temperature at 20 0C to 140 0C’. Energy transferred = mass x sp. ht. cap. x temperature change E = m x c x θ c) E = 2 x 1200 x (140 – 20) E = 2 x 1200 x 120 E = 288,000 J = 288 kJ

  18. Specific heat capacity ‘c’ B grade: calculation: Calculate the energy required to raise 2 kg of the substances below a) Aluminium 880 J/kg/ 0 C from room temperature at 20 0C to 80 0C’. b) Copper 380 J/kg/ 0 C from 0 0C to 100 0C c) Oil 1200 J/kg/ 0 C from room temperature at 20 0C to 140 0C’. Energy transferred = mass x sp. ht. cap. x temperature change E = m x c x θ c) E = 2 x 1200 x (140 – 20) E = 2 x 1200 x 120 E = 288,000 J = 288 kJ

  19. Specific heat capacity ‘c’ A grade: calculation: Calculate the specific heat capacity of water if 21,000 J are required to raise 0.5Kg from 200C to 300C. Energy transferred = mass x sp. ht. cap. x temperature change E = m x c x θ 21,000 = m x c x θ 21,000 = 0.5 x c x (30-20) 21,000 = 0.5 x c x 10 21,000 = 5 c 21,000 = c 5 c = 4200 J/Kg/0C

  20. Specific heat capacity ‘c’ A grade: calculation: Calculate the specific heat capacity of water if 21,000 J are required to raise 0.5Kg from 200C to 300C. Energy transferred = mass x sp. ht. cap. x temperature change E = m x c x θ 21,000 = m x c x θ 21,000 = 0.5 x c x (30-20) 21,000 = 0.5 x c x 10 21,000 = 5 c 21,000 = c 5 c = 4200 J/Kg/0C

  21. Q1 B grade: calculation: Calculate the energy required to raise 2 kg of the substances below a) Aluminium 880 J/kg/ 0 C from room temperature at 20 0C to 80 0C’. b) Copper 380 J/kg/ 0 C from 0 0C to 100 0C c) Oil 1200 J/kg/ 0 C from room temperature at 20 0C to 140 0C’. Q2 A grade: calculation: Calculate the specific heat capacity of water if 21,000 J are required to raise 0.5Kg from 200C to 300C.

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