January 2023

Biogas as a source of energy

By |2022-09-15T12:38:58+02:00January 24th, 2023|Notes, O Level Science Notes, Ordinary Level Notes|

ZIMSEC O Level Combined Science Notes: Biogas as a source of energy

  • Biogas is the gas that is obtained from fermenting manure and other organic waste
  • It is a mixture of methane, carbon dioxide and hydrogen sulphide
  • Cattle manure is commonly used as a waste to feed biogas plants
  • Small plants have been built in some parts of Zimbabwe

    • […]

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Conductors and insulators

By |2022-09-15T12:38:50+02:00January 24th, 2023|Notes, O Level Science Notes, Ordinary Level Notes|

Conductors and Insulators. Image credit sci-toys.com Conductors and Insulators. Image credit sci-toys.com ZIMSEC O Level Combined Science Notes: Conductors and insulators

  • A conductor is a material that allows electrons to move from one atom to another
  • Conductors/Conducting materials cannot be charged unless they are held using an insulating material to prevent […]
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A simple D.C motor

By |2022-09-15T12:38:32+02:00January 24th, 2023|Notes, O Level Science Notes, Ordinary Level Notes|

dc_motor-min DC motor. Image credit kostov-motors.com ZIMSEC O Level Combined Science Notes: Experiment: Demonstrating that an electric wire moves in a magnetic field

  • A DC motor converts direct electric current into kinetic energy
  • It has a stator
  • Stator-a stationary magnet found within a DC motor
  • It also has a many coils […]
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Experiment: Testing the strength of various joints

By |2022-09-15T12:38:23+02:00January 24th, 2023|Notes, O Level Science Notes, Ordinary Level Notes|

Welding joints. Image credit youtube.com Welding joints. Image credit youtube.com ZIMSEC O Level Combined Science Notes:Experiment: Testing the strength of various joints

Aim: To test the strength of various joints in beams

Materials:  pieces of metal,poplar wood, glue, drawing pins/nails, bolts and nuts, old plastic rulers, burner, bricks/clamp, welding equipment/burner

Method Testing [...] </p srcset=

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Machines

By |2022-09-15T12:38:16+02:00January 24th, 2023|Notes, O Level Science Notes, Ordinary Level Notes|

Gears in a machine. Image credit wall.alphacoders.com Gears in a machine. Image credit wall.alphacoders.com ZIMSEC O Level Combined Science Notes: Machines

  • A machine is a device that makes work easier either by:
  • Reducing the effort (force) required to lift the load or
  • By changing the direction in which the effort is […]
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Immunity and Immunisation

By |2022-09-15T12:37:57+02:00January 24th, 2023|Notes, O Level Science Notes, Ordinary Level Notes|

Sindiso Marume holding her brother's health card. Image credit irinnews.org Sindiso Marume holding her brother’s health card. Image credit irinnews.org ZIMSEC O Level Combined Science Notes: Disease:Immunity and Immunisation

  • Immunity-is the ability of the body to resist diseases
  • There are various types of immunity:
  • Antigen-is any substance that causes […]
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Contraception: Abstinence

By |2022-09-15T12:37:50+02:00January 24th, 2023|Notes, O Level Science Notes, Ordinary Level Notes|

Couple holding hands. Image credit neguswhoread.com Couple holding hands. Image credit neguswhoread.com ZIMSEC O Level Combined Science Notes:Contraception: Abstinence

  • It involves total avoidance of sexual intercourse

Adavantages

  • Many couples agree to wait until marriage
  • There is no risk of contracting  Sexually Transmitted Infections
  • It is 100% effective
  • It is supported by most religious […]
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The Test for starch

By |2022-09-15T12:41:57+02:00January 24th, 2023|Notes, O Level Science Notes, Ordinary Level Notes|

  • During the process of photosynthesis, a plant absorbs, a process which is aided by the presence of chlorophyll in the leaf
  • This enables the plant to convert carbon dioxide and water into glucose
  • Some of this glucose is used up by the plant however
  • Any excess is turned into starch for storage
  • You can, therefore, test a plant’s leaf for starch in […]
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