February 2025

Strength to Mass ratio

By |2025-02-12T09:13:19+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

The cross section of beams The cross section of beams ZIMSEC O Level Combined Science Notes: Strength to Mass ratio

  • Engineers do away with materials that are under little stress so as to be able to build efficient structures in terms of weight and cost
  • The material that lies close to the neutral […]
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The reaction of metals with dilute acids

By |2025-02-12T09:38:29+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

ZIMSEC O Level Combined Science Notes: Experiment: The reaction of metals with dilute acids

  • Metals also react with dilute acids such as
  • Dilute hydrochloric acid
  • Hydrogen gas is released as a by product of the reaction
  • Metals such as calcium, magnesium and zinc that react with water react even more vigorously with dilute acids
  • Metals that react with […]
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Experiment: Making acidic and alkaline solutions

By |2025-02-12T09:08:03+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Burning sulpher Burning sulpher ZIMSEC O Level Combined Science Notes: Experiment: Making acidic and alkaline solutions

Aim: To make acidic and alkaline solutions

Materials: sodium oxide, magnesium oxide, aluminium oxide, zinc oxide, unversal indicator, deflagrating spoon, sulpher, powdered carbon

Method

  1. Dissolve a very small amount of sodium oxide in half a test tube of water
  2. Add 2 drops […]
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Copper and its alloys

By |2025-02-12T09:24:43+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Copper and its alloys. Image credit zzhi.com Copper and its alloys. Image credit zzhi.com ZIMSEC O Level Combined Science Notes:Copper and its alloys

  • Copper is a common element found in the earth’s crust
  • It can occur as an element, as copper oxide or as sulphide ore
  • In Zimbabwe:
  • Sulphide copper deposits […]
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Rusting and Painting

By |2025-02-12T09:39:40+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

ZIMSEC O Level Combined Science Notes: Rusting and Painting

  • Painting is a popular method used to prevent rusting
  • The structure to be painted is cleaned using an acidic solution
  • This removes existing rust and dirt
  • Sand paper/scrubbing material  is also used to clean the surface to be painted
  • The surface is then left to dry
  • Once it is dry […]
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Biogas as a source of energy

By |2025-02-12T09:06:04+02:00February 12th, 2025|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 |2025-02-12T09:18:48+02:00February 12th, 2025|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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