Temperature AND Time

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How to calibrate a thermometer?
How does the pendulum clock work?
How to adjust pendulum clocks?

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Temperature AND Time

  1. 1. How to calibrate a thermometer? How does the Pendulum Clock work?
  2. 2. How to calibrate a thermometer?
  3. 3. Thermometer is an i ____________ which measures __________________. Temperature is a p ___________________ q ___________________ which measures the d _________ of h _______________ of an object. <ul><li>Two common types of thermometers used in school are: </li></ul><ul><li>_________________________ thermometer </li></ul><ul><li>_________________________ thermometer </li></ul>
  4. 4. Thermometer is an i ____________ which measures __________________. Temperature is a p ___________________ q ___________________ which measures the d _________ of h _______________ of an object. <ul><li>Two common types of thermometers used in school are: </li></ul><ul><li>_________________________ thermometer </li></ul><ul><li>_________________________ thermometer </li></ul>nstrument temperature Alcohol-in-glass Mercury-in-glass hysical uantity egree otness
  5. 5. Temperature For more details, go to http://en.wikipedia.org/wiki/SI SI unit = International System of Units SI unit °C means
  6. 6. Temperature For more details, go to http://en.wikipedia.org/wiki/SI SI unit = International System of Units Kelvin (K) SI unit degree C elcius ° C means
  7. 7. Parall a x Error (‘ reading error caused by incorrect eye position’)
  8. 8. Parall a x Error (‘ reading error caused by incorrect eye position’)
  9. 9. 18 °C 19 °C 17 °C How to read a thermometer?
  10. 10. 18 °C 17 °C <ul><li>When reading a thermometer: </li></ul><ul><li>The thermometer should be vertical . </li></ul><ul><li>Eyes should be at the same level as the top of the liquid in glass. </li></ul>How to read a thermometer?
  11. 11. What is hot ? <ul><li>When washing our hands, why does the tap water feels cold? </li></ul><ul><li>What is ‘temperature’? </li></ul>Palm Tap water Temperature
  12. 12. What is hot ? <ul><li>When washing our hands, why does the tap water feels cold? </li></ul><ul><li>What is ‘temperature’? </li></ul>The tap water has smaller temperature than our hands. Temperature is a physical quantity which measures the hotness of an object. Palm Tap water Temperature
  13. 13. Thermometer Theory Workbook p.19 Q.2, 3
  14. 16. How to calibrate a thermometer? <ul><li>calibrate ( verb. ) </li></ul><ul><ul><ul><li>mark scales on an instrument </li></ul></ul></ul><ul><ul><ul><li>by comparing with standards </li></ul></ul></ul>
  15. 17. <ul><li>calibrate ( verb. ) </li></ul><ul><ul><ul><li>mark scales on an instrument </li></ul></ul></ul><ul><ul><ul><li>by comparing with standards </li></ul></ul></ul>0 °C 100 °C
  16. 18. <ul><li>Mark the ice point (0 °C) </li></ul><ul><ul><li>and measure its mercury length (3cm). </li></ul></ul>3 cm
  17. 19. <ul><li>2. Mark the steam point (100 °C) </li></ul><ul><ul><li>and measure its mercury length (13cm). </li></ul></ul>13 cm
  18. 20. <ul><li>3. Calculate the mercury length for 1°C and </li></ul><ul><ul><li>by graduation, mark the scale onto the thermometer. </li></ul></ul>3 cm 13 cm 13cm - 3cm 0 °C 100 °C 100 °C - 0°C 0.1 cm 50 °C (50x0.1) cm
  19. 21. 4. 3 cm 13 cm 0 °C 100 °C water 5.2 cm 5.2cm - 3cm x 100 °C 13cm - 3cm 22 °C Unknown temperature can be determined by proportionality in mercury length. For example: ??? °C
  20. 22. Thermometer Theory Workbook p.19 Q.5
  21. 23. The melting point of ice is 0 °C . The boiling point of water is 100 °C . <ul><li>Place the thermometer into ice. </li></ul><ul><li>Mark the ice point at 0°C. </li></ul><ul><li>2. Place the thermometer into steam (or boiling water). </li></ul><ul><li>Mark the steam point at 100°C. </li></ul><ul><li>3. Divide the length between these two marks by 100 and hence obtain the length for each division. Each division equals to 1°C. </li></ul><ul><li>By graduation, mark these 100 equal divisions onto the thermometer. </li></ul>
  22. 25. How does the Pendulum Clock work?
  23. 26. Time
  24. 27. Time For more details, go to http://en.wikipedia.org/wiki/SI SI unit = International System of Units 1 min = ‘ s ’ means SI unit 1 h = ‘ min ’ means ‘ h ’ means
  25. 28. Time For more details, go to http://en.wikipedia.org/wiki/SI SI unit = International System of Units 60 s 1 min = second ‘ s ’ means second (s) SI unit 60 min 1 h = minute ‘ min ’ means hour ‘ h ’ means
  26. 29. Electronic Stopwatch is an instrument which measures ____________. Accuracy = s ‘ Start’ button ‘ Stop’ button
  27. 30. Electronic Stopwatch is an instrument which measures ____________. Accuracy = s
  28. 31. Pendulum Invented by Ibn Yunus ابن يونس Used by Galileo to measure time
  29. 32. Pendulum Clock
  30. 33. Pendulum bob length <ul><li>Pendulum length is measured </li></ul><ul><ul><li>from the centre of the bob at lowest position </li></ul></ul><ul><ul><ul><ul><ul><li>to the top of the string. </li></ul></ul></ul></ul></ul>
  31. 34. Pendulum 1 ‘ oscillation’ = 1  2  3  2  1 Period (T) = time taken for 1 oscillation = ‘how fast the pendulum is swinging’
  32. 35. Pendulum Average Time taken for 10 oscillation = 10 10 10 Period (T) = time taken for 1 oscillation = Time taken (s) Number of Oscillation
  33. 36. Pendulum Theory Workbook p.17 Q 4
  34. 37. “ angle of displacement” “ Period” Therefore, the size of the swing doesn’t affect Period.
  35. 38. Pendulum 1 ‘ oscillation’ = 1  2  3  2  1 Period (T) = time taken for 1 oscillation = ‘how fast the pendulum is swinging’ Fast or Slow Period (T) 10 s 2 s
  36. 39. Pendulum 1 ‘ oscillation’ = 1  2  3  2  1 Period (T) = time taken for 1 oscillation = ‘how fast the pendulum is swinging’ Fast Slow Fast or Slow Period (T) 10 s 2 s
  37. 40. Pendulum Clock When the clock is too slow, decrease the Period. When the clock is too fast, increase the Period.
  38. 41. Pendulum Clock When the clock is too slow, decrease the Period. When the clock is too fast, increase the Period.
  39. 42. Pendulum http://en.wikipedia.org/wiki/Pendulum Period ( = Time taken for 1 oscillation) ( = ‘ how fast is the pendulum swinging ’) Pendulum Length
  40. 43. Pendulum bob length <ul><li>Pendulum length is measured </li></ul><ul><ul><li>from the centre of the bob at lowest position </li></ul></ul><ul><ul><ul><ul><ul><li>to the top of the string. </li></ul></ul></ul></ul></ul>
  41. 44. Pendulum http://en.wikipedia.org/wiki/Pendulum Period ( = Time taken for 1 oscillation) ( = ‘ how fast is the pendulum swinging ’) Pendulum Length constant numbers
  42. 45. T = l to When l = 10 T = 10 When l = 20 T = 20 Remove constant numbers and simplify T = l When l increases, T also increases. Therefore, Longer l , Longer T .
  43. 46. Pendulum http://en.wikipedia.org/wiki/Pendulum Period Pendulum Length Longer Length, Longer Period.
  44. 47. Pendulum http://en.wikipedia.org/wiki/Pendulum Period Pendulum Length Bob Mass doesn’t affect Period.
  45. 48. Pendulum http://en.wikipedia.org/wiki/Pendulum Period Pendulum Length Swing size doesn’t affect Period. swing size = “angle of displacement”
  46. 49. Pendulum http://en.wikipedia.org/wiki/Pendulum Period Pendulum Length <ul><li>Longer Length , Longer Period . </li></ul><ul><li>Bob mass doesn’t affect Period. </li></ul><ul><li>Swing size doesn’t affect Period. </li></ul>
  47. 50. Pendulum Theory Workbook p.18 Q 6
  48. 52. <ul><li>Build a pendulum using a bob and a piece of string. </li></ul><ul><li>Measure the time taken for 10 oscillations by this pendulum. Calculate the average time taken for 1 oscillation (‘the Period’). </li></ul><ul><li>With the same pendulum length, use a different bob with bigger mass. Repeat the same measure for its Period. </li></ul><ul><li>Compare the two Period measurements. </li></ul>
  49. 53. Pendulum Clock Longer Length, Longer Period. When the clock is too slow, decrease the Period How? When the clock is too fast, increase the Period. How?
  50. 54. Pendulum Clock Longer Length, Longer Period. When the clock is too slow, decrease the Period How? Decrease the Pendulum Length. When the clock is too fast, increase the Period. How? Increase the Pendulum Length.
  51. 55. http://en.wikipedia.org/wiki/Pi_(film)
  52. 56. Homework Theory Workbook p.18-20 For today’s slides, go to: www.slideshare.net Login: tvos0619 Password: 1234qwer

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