February 2025

Extraction of iron: The blast furnace

By |2025-02-12T09:21:45+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

ZIMSEC O Level Combined Science Notes: Extraction of iron: The blast furnace

  • After iron ore is mined it is send to the blast furnace
  • Iron is extracted from its ore in a blast furnace

 

The structure of a blast furnace. Image credit s-cool.co.uk The structure of a blast furnace. Image credit s-cool.co.uk

    […]
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Experiment Chrome plating a nickel cathode

By |2025-02-12T09:36:06+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Nickel and Chrome plate. Image credit 1911forum.com Nickel and Chrome plate. Image credit 1911forum.com ZIMSEC O Level Combined Science Notes: Experiment Chrome plating a nickel cathode

Aim: To chrome plate a nickel cathode

Materials: nickel-plated  electrode, lead electrode, beaker, chromic acid

Method

  1. Set up an electrolytic cell using a nickel plated cathode from this […]
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Coal as a fuel

By |2025-02-12T09:03:21+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Coal Mining at Hwange. Image credit chronicle.co.zw Coal Mining at Hwange. Image credit chronicle.co.zw ZIMSEC O Level Combined Science Notes: Coal fuel

  • Coal is a common solid fuel
  • It is a non-renewable resource
  • It is used as a raw material by industries such as at ZISCO and less commonly as a […]
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Social and economic factors to consider when using fuels

By |2025-02-12T09:16:45+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Oil spills are destructive to vegitation. Image credit africanewscircle.com Oil spills are destructive to vegetation. Image credit africanewscircle.com ZIMSEC O Level Combined Science Notes: Social and economic factors to consider when using fuels

  • The extraction and consumption of fuels has led to a lot of problems in recent years
  • Problems include:

    • […]

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Perfecting the electric cell

By |2025-02-12T09:34:36+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Polarisation in a simple cell Polarisation in a simple cell ZIMSEC O Level Combined Science Notes: Perfecting the electric cell

Voltage/Potential difference

  • The voltage between the two electrodes is dependent on the type of electrode used
  • When magnesium and copper are used the potential difference between the two electrodes is fairly high

    • […]

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Uses of generators

By |2025-02-12T08:58:47+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Generators have many uses.Image credit wheelerdealers.co.zw Generators have many uses.Image credit wheelerdealers.co.zw ZIMSEC O Level Combined Science Notes:  Uses of generators

  • In Zimbabwe there a number of Power Stations that generate electricity
  • In practice most generators are AC rather than  DC generators
  • At Kariba there is a Hydro Electric station

    • […]

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Introduction to Trusses

By |2025-02-12T09:13:06+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Roof trusses. Image credit myrooff.com Roof trusses. Image credit myrooff.com ZIMSEC O Level Combined Science Notes: Introduction to Trusses

  • A truss is a supporting framework for a roof, bridge or any other large structure
  • Box and rectangular truss frameworks are inherently weak and susceptible to shear force

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Experiment: To compare the resistance of different woods to termite attack

By |2025-02-12T09:28:10+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Treated poles. Image credit lynnridgetimbers.co.za Treated poles. Image credit lynnridgetimbers.co.za ZIMSEC O Level Combined Science Notes: Experiment: To compare the resistance of different woods to termite attack

Aim: To compare the resistance of different types of wood to termite attack

Materials: gloss paint, used motor oil, creosote, 4 samples of softwood (pine), 4 samples of […]

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The concept of pressure

By |2025-02-12T08:59:22+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

 ZIMSEC O Level Combined Science Notes: The concept of pressure
  • Pressure is the force acting over an area
  • In such pressure is usually the force per unit area exerted by a fluid/gas
  • over a surface with which it is in contact
  • \text{Pressure=} \dfrac{Force}{Area}
  • If a big force is exerted over a small area it results high pressure
  • An example […]
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Experiment: Finding conditions necessary for growth of microorganisms

By |2025-02-12T09:19:51+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Mouldy bread and their conditions. Image credit Mouldy bread and their conditions. Image credit wordpress.com ZIMSEC O Level Combined Science Notes: Experiment: Finding conditions necessary for growth of microorganisms

Aim: To determine factors affecting the growth of microorganisms in food

Materials:  3 containers with sterilized lids, brad, milk, burners, drying agent (calcium chloride)

Method

  1. Pour […]
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