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Science form 1(Chapter5-part1)

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  1. 1. SCIENCE Form 1 UNIT 5 .3 ,5.4 The Air Around Usyschow88@smkbpj(a) 1
  2. 2. 5.3OXYGEN ISNEEDED FORRESPIRATION yschow88@smkbpj(a) 2
  3. 3. yschow88@smkbpj(a) 3
  4. 4. What is respiration? The chemical process in which energy is released from the breaking down of food is called respiration.• Where does respiration take place? Respiration occur in the body cells. yschow88@smkbpj(a) 4
  5. 5. How does respiration take part?• Respiration requires oxygen. Oxygen oxidises the glucose in the body cells to release energy.• Carbon dioxide and water vapour are the waste products in respiration: Gucose Oxygen Energy Carbon Water dioxide vapour yschow88@smkbpj(a) 5
  6. 6. yschow88@smkbpj(a) 6
  7. 7. Experiment to find the difference in oxygen content between inhaled and exhaled air. yschow88@smkbpj(a) 7
  8. 8. What gas is needed for respiration?• Responding- Contents of air in the boiling tube• Constant- The presence of living organisms• Manipulated- The position of mercury thread yschow88@smkbpj(a) 8
  9. 9. Result• The mercury thread of A and B moves towards the boiling tubes.• While the mercury thread at boiling tube C does not change.Conclusion: Oxygen is needed by animals and plants during respiration. yschow88@smkbpj(a) 9
  10. 10. Do organisms release carbon dioxide duringrespiration?• Responding - Contents of air in the boiling tube• Constant - The presence of living organisms• Manipulated -The colour change carbonate indicator (bicarbonate indicator) yschow88@smkbpj(a) 10
  11. 11. Result The hydrogen carbonate indicator in tube X and Y change from red to yellow while yellow, the hydrogen carbonate indicator in tubes Z does not change.Conclusion Organisms release carbon dioxide during respiration. yschow88@smkbpj(a) 11
  12. 12. Experiment to show the products of respiration yschow88@smkbpj(a) 12
  13. 13. yschow88@smkbpj(a) 13
  14. 14. yschow88@smkbpj(a) 14
  15. 15. Check point yschow88@smkbpj(a) 15
  16. 16. yschow88@smkbpj(a) 16
  17. 17. yschow88@smkbpj(a) 17
  18. 18. Summary so far :Humans require chemical energy to carry out life processes.This energy is obtained when sugars from digested food arebroken down during respiration. yschow88@smkbpj(a) 18
  19. 19. Demand for energy yschow88@smkbpj(a) 19
  20. 20. 5.4OXYGEN IS NEEDED FORCOMBUSTION yschow88@smkbpj(a) 20
  21. 21. Combustion Combustion is the burning of substancesin air.The substance (fuel), reacts rapidly withoxygen to produce heat and light.Combustion is a chemical process because during this process new substances are formed. yschow88@smkbpj(a) 21
  22. 22. Conditions for combustionCombustion can only occur when these threeconditions are satisfied, that is, the presence of:a. a substance that can burn, or a fuel (2 types) i. Carbon ii. Hydrocarbonb. Oxygenc. Heat to warm the fuel until it reaches ignition temperature. yschow88@smkbpj(a) 22
  23. 23. The combustion of carbonsThe combustion ofcarbons like firewood,charcoal and coalproduces carbondioxide and energy inthe form of heat andlight Carbon + oxygenCarbon dioxide + energy yschow88@smkbpj(a) 23
  24. 24. The combustion of hydrocarbons The combustion of hydrocarbons which are compounds of hydrogen and carbon, produces carbon dioxide, water and energy in the form of heat and light. Examples of hydrocarbons:1. Kerosene2. Petrol3. Diesel4. wax. yschow88@smkbpj(a) 24
  25. 25. The combustion of hydrocarbonsHydrocarbon + oxygen Carbon dioxide + Water + energy yschow88@smkbpj(a) 25
  26. 26. yschow88@smkbpj(a) 26
  27. 27. 5.5 AIR POLLUTION yschow88@smkbpj(a) 27
  28. 28. Substances that Pollute the Air• Air pollution occurs when air contains pollutants.• Pollutants are harmful substances that are released into the environment. released into the environment.• Air pollution is the result of the acts of human. yschow88@smkbpj(a) 28
  29. 29. Thinning of the ozone layer• Chlorofluorocarbon (CFC) form aerosol cans, refrigerators, air conditioners and electronic factories.• Destroys the ozone layer in Earths atmosphere• Ultraviolet light causes cataracts and skin cancer and skin cancer yschow88@smkbpj(a) 29
  30. 30. Acid Rain• Nitrogen dioxide, nitrogen monoxide and sulphur dioxide dissolve in rain drops to form acid rain. yschow88@smkbpj(a) 30
  31. 31. Acid Rain yschow88@smkbpj(a) 31
  32. 32. yschow88@smkbpj(a) 32
  33. 33. 5.6THE IMPORTANCE OFKEEPING THE AIR CLEAN yschow88@smkbpj(a) 33
  34. 34. • Nowadays many of our surrounding peoples are live in suffering of health problems such as lung cancer, asthma, skin disease, impaired of eye-sight and etc• Accidents and breath problems increases due to air pollution such as haze• Ways to keep the air clean: i. Plant more trees at surrounding Ii. Stop deforestation Iii. Encourage habit of recycling by discarding materials made from wood, plastic, glasses and tin yschow88@smkbpj(a) 34
  35. 35. Ways to keep the air cleaniv. Practice car-pooling or prefer walking of short distance instead of drivingv. Practice using solar Do not smokevii. Avoid open burning of waste products, such as rubbish and plastics yschow88@smkbpj(a) 35