February 2025

Ethanol as a source of energy

By |2025-02-12T09:07:30+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

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

  • Ethanol is also known as alcohol
  • It is made by fermenting plants with a high sugar content
  • Sugar cane is commonly used to make ethanol in Zimbabwe
  • The plant is grown in Zimbabwe’s Lowveld
  • Water from Mutirikwe and Bangala Dams is used to irrigate the crop
  • Biomas is […]
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Science:Lighting

By |2025-02-12T09:19:27+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Lightining is a result of electrostatic discharge. Image credit zmescience.com Lightining is a result of electrostatic discharge. Image credit zmescience.com ZIMSEC O Level Combined Science Notes: Conductors and insulators

  • Clouds are poor conductors because they are made of mostly water particles
  • They may become charged due to friction forces within them […]
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Photovoltaic cells/Solar Panels

By |2025-02-12T09:37:35+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Solar Panels. Image credit digitaltrends.com Solar Panels. Image credit digitaltrends.com ZIMSEC O Level Combined Science Notes: Photo-voltaic cells/Solar Panels

  • Solar cells convert radiation from the sun into electrical energy
  • These cells are mad from silicon
  • Which is a semiconducting material
  • While most metals are good conductors of electricity because they […]
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Experiment:Making a model electric motor

By |2025-02-12T09:03:40+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

An electric motor. Image credit jeffryerickson.com An electric motor. Image credit jeffryerickson.com ZIMSEC O Level Combined Science Notes: Experiment:Making a model electric motor

Aim:  To make a model electric motor

Materials: copper wires, switch, coil (made from varnished copper), magnet, paper clips, rechargeable battery

Method

  1. Set up the coil and magnet as shown in the […]
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Joining trusses

By |2025-02-12T09:19:50+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Gang nails on a wooden truss. Gang nails on a wooden truss. Image credit naildesignart.biz ZIMSEC O Level Combined Science Notes:Joining trusses

  • In the real world various techniques are used to join trusses in ways that prevent joints from becoming points of weakness
  • Steel trusses are usually joined by welding […]
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Machines:Levers

By |2025-02-12T09:36:07+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

ZIMSEC O Level Combined Science Notes: Machines:Levers

  • A lever is a very simple machine
  • It is made up of a rigid bar resting on a pivot,
  • used to move a  load with one end
  • by applying an effort on the other end
  • Examples of machines that use the lever are:
  • scissors, human arm, hand pump, claw hammer, shovel

 

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Hydraulic Jack

By |2025-02-12T09:09:30+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

ZIMSEC O Level Combined Science Notes: Hydraulic Jack

  • Has a large ram attached to the piston in a large cylinder

The diagram of the Hydraulic Jack. Image credit slideplayer.com

The diagram of the Hydraulic Jack. Image credit slideplayer.com

  • A piston in a small cylinder is worked by a handle
  • Pressure on this cylinder when […]
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Diseases:HIV/AIDS

By |2025-02-12T09:30:54+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Zimbabwe nurse and health worker. Image credit icrc.org Zimbabwe nurse and health worker. Image credit icrc.org ZIMSEC O Level Combined Science Notes: Disease:Immunity and Immunisation

HIV and Its effects

  • HIV stands for Human Immunodeficiency Virus
  • It lives in the body fluids including blood, saliva, semen, tears etc
  • It enters the body in […]
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Causes of infertility

By |2025-02-12T08:57:00+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Sterility can cause strain in a relationship. Image credit colossiansfamilynetwork.org Sterility can cause strain in a relationship. Image credit colossiansfamilynetwork.org ZIMSEC O Level Combined Science Notes: Causes of infertility

  • Sterility is the inability to reproduce
  • There are a number of causes for sterility
  • Low sperm count (makes it […]
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Factors,Inputs and outputs of photosynthesis

By |2025-02-12T09:36:23+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

ZIMSEC O Level Combined Science: The test for starch

The requirements of photosynthesis

  • As already mentioned the food making process in plants is called photosynthesis.
  • In order for a plant to […]
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