February 2025

Heating metals in air

By |2025-02-12T09:32:08+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

 ZIMSEC O Level Combined Science Notes: Heating metals in air
  • Some metals react with oxygen in the air at ordinary (room) temperature
  • Others only react with oxygen if they are heated in air
  • They may do this readily and release large amounts of energy in the process
  • Some metals hardily react at all even at very high temperatures

    • […]

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Introduction to acids

By |2025-02-12T08:59:45+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

ZIMSEC O Level Combined Science Notes: Introduction to acids

  • A lot of everyday materials are acidic
  • This means that they contain an acid
  • Examples of everyday materials that contain acids are:
  • Lemons and other citric fruits as well as materials that contain these for example Orange crush
  • Vinegar (contains ethanoic/acetic acid)
  • Battery acid (sulphuric acid)
  • Other acids include: […]
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Reversible reactions

By |2025-02-12T09:17:50+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

ZIMSEC O Level Combined Science Notes: Reversible reactions

  • In a reversible reaction there is a forward reaction
  • And a backward reaction
  • Both take place at the same time
  • As a result there is an equilibrium between the reagents and their products
  • That is at some point during the reaction process the amounts of both the reagents and their […]
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The electroplating process

By |2025-02-12T09:32:31+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Chome plated metal. Image credit MediaWiki Chome plated metal. Image credit MediaWiki ZIMSEC O Level Combined Science Notes: The electroplating process

  • Metals can be protected from corrosion by plating (covering) them with a less reactive metal
  • The metal which does not react with oxygen protects the more reactive metal underneath it

    • […]

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The manufacture of fertilizers

By |2025-02-12T08:59:33+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

ZIMSEC O Level Combined Science Notes:  The manufacture of fertilisers

  • Some of the nitric acid produced at Sable Chemicals is used to make ammonium nitrate fertilizer
  • It is used as an input (feedstock) for the fertilizer plant at both Sable and Zimphos
  • To maintain soil fertility nitrogen containing compounds are added to the soil
  • Some of these fertilizers are […]
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The carburetor

By |2025-02-12T09:14:26+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

A carburettor is an important part of the Petrol engine. Image credit MediaWiki A carburettor is an important part of the Petrol engine. Image credit MediaWiki ZIMSEC O Level Combined Science Notes: The carburetor

  • A carburettor is an essential part of Petrol engines
  • A typical carburettor has the following parts:
  • An […]
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Electrical Power

By |2025-02-12T09:30:22+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

ZIMSEC O Level Combined Science Notes: Electrical Power

  • Electric power is the rate of doing work or the rate of of using energy
  • Electric power is the rate which an electrical device is converting electrical energy into heat or light or any other form of energy e.g kinetic energy in an electric motor
  • When current flows through a wire some of […]
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Experiment: Demonstrating how current is induced

By |2025-02-12T09:45:24+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Inducing a current using a magnet. Image credit youtube.com Inducing a current using a magnet. Image credit youtube.com ZIMSEC O Level Combined Science Notes: Experiment: Demonstrating how current is induced

Aim: To demonstrate electromagnetic induction

Materials: an electric coil (you can make one using varnished copper), galvanometer with a zero at the centre, connecting leads […]

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Comparing the strength of cylindrical and square tube beams

By |2025-02-12T09:09:42+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Testing the strength of a beam Testing the strength of a beam ZIMSEC O Level Combined Science Notes: Experiment: Comparing the strength of cylindrical and square tube beams

Aim:  To compare the strength of cylindrical and square tubes

Materials: thin cardboard, tin can, sand and glue.

Method

  1. Make a cylindrical tube by rolling a piece […]
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Experiment: To compare the shear and tensile strength of sponge rubber and soft wood

By |2025-02-12T09:26:19+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Sheets of made of sponge rubber. Image credit rollsheetrubber.com Sheets of made of sponge rubber. Image credit rollsheetrubber.com ZIMSEC O Level Combined Science Notes: Experiment: To compare the shear and tensile strength of sponge rubber and soft wood

Aim: To compare the shear and tensile strength of sponge rubber and a softwood

Materials: wooden ice-cream […]

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