February 2025

Neutralisation/Salts

By |2025-02-12T09:10:01+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

ZIMSEC O Level Combined Science Notes: Neutralisation/Salts

  • The acidity and alkalinity of a solution can be represented on the pH scale
  • If the pH is low i.e less than 7 then the solution is acidic
  • If the pH is high i.e higher than 7 then the solution is alkaline
  • If a solution has a pH of 7 […]
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Extraction of copper from sulphides

By |2025-02-12T09:26:36+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

ZIMSEC O Level Combined Science Notes:Extraction of copper from sulphides

  • Copper is extracted from various types of ore including sulphide ores
  • For example copper ores found on the Great Dyke near Mhangura is of the sulphide type
  • Once the sulphide ore is extracted from the earth
  • It is crushed to form a very fine powder which is then further […]
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Liquification of air

By |2025-02-12T09:40:17+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Sable chemicals plant. Image credit zimeye.net Sable chemicals plant. Image credit zimeye.net ZIMSEC O Level Combined Science Notes: Liquification of air

  • In Zimbabwe the air liquification plant is at Sable Chemicals
  • Two main components of air are separated:
  • Nitrogen and Oxygen
  • These two gases are used in either liquid or gas form

    • […]

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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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A simple D.C motor

By |2025-02-12T09:02:26+02:00February 12th, 2025|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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Types of joints

By |2025-02-12T09:17:22+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Brazing. Image credit samarthenggworks.com Brazing. Image credit samarthenggworks.com ZIMSEC O Level Combined Science Notes:Types of joints

  • The main function of a joint is to transmit load from one part of a structure to another
  • This usually results in the joint being subjected to a lot of stress and weakening the structure

    • […]

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Suspension bridge

By |2025-02-12T09:32:16+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

The Hong Kong Bridge. Image credit plus.maths.org The Hong Kong Bridge. Image credit plus.maths.org ZIMSEC O Level Combined Science Notes: Suspension bridge

  • Old suspension bridges were usually built using rope/vegetable fibre
  • The ropes could withstand tension forces while they were new but they would quickly deteriorate
  • Suspension bridges are usually constructed […]
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Pumps: Blair pump

By |2025-02-12T09:05:51+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

The blair pump The blair pump ZIMSEC O Level Combined Science Notes: Pumps: Blair pump

  • The pumped was first developed in 1976
  • The design was further refined at the Blair Research Laboratory in Harare
  • Various models have been subsequently designed and made
  • Cumulating in the famous Type B bush pump
  • It is popularly known […]
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