February 2025

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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Machines: Gears

By |2025-02-12T09:45:26+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

ZIMSEC O Level Combined Science Notes: Machines: Gears

  • A gear is a toothed wheel
  • These toothed wheels transfer motion to one another using their teeth
  • Gears are also known as cogs wheels
  • The teeth on a gear are also known as cogs
  • These cog wheels are usually mounted on shafts
  • The teeth of adjacent cogs fit the grooves of the […]
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Teeth and tooth decay

By |2025-02-12T09:16:38+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Good dental care is part of human health. Image credit claimfame.com Good dental care is part of human health. Image credit claimfame.com ZIMSEC O Level Combined Science Notes: Teeth and tooth decay

  • While people enjoy food of all varieties
  • Some types of food
  • For example sweets, chocolates, carbonated drinks, cakes and […]
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Effects of population growth on natural resources

By |2025-02-12T09:00:15+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Environmental degradation in Epworth. Image credit newsday.co.zw Environmental degradation in Epworth. Image credit newsday.co.zw ZIMSEC O Level Combined Science Notes: Population and natural resources

Environmental Effects

  • Soil erosion
  • Deforestation
  • Desertification
  • Reduced soil fertility

Social Effects

  • Overcrowding
  • Criminal activities
  • Immorality
  • Poor health services
  • Poor education facilities
  • General increase in poverty

To […]

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