February 2025

The mammal heart

By |2025-02-12T09:20:21+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

The structure of the human heart. The structure of the human heart. ZIMSEC O Level Combined Science Notes: The mammal heart

  • Is made up of muscle which contracts continuously throughout the mammal’s life.
  • The number of contractions differ from mammal to mammal
  • In elephants it contracts about 25 times/minute
  • In humans it contracts about 70-80 […]
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Experiment comparing the particle size of soils

By |2025-02-12T09:40:50+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Soil sedimentation test. Soil sedimentation test. ZIMSEC O Level Combined Science Notes: Experiment comparing the particle size of soils  

Materials: samples of sandy, loamy and clay soils, 3 measuring cylinders/tall transparent containers, water

Method

  1. Place sample of each soil sample into a tall container to about a quarter of its height
  2. Add water to until […]
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An introduction to Beams and their types

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

beams_introduction-min Common types of beams and their associated forces ZIMSEC O Level Combined Science Notes: An introduction to Beams and their types

  • A beam is any material that is supported so that it can hold a load
  • A simple beam is a length of material e.g steel supported along its length so that […]
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Experiment: Heating metals in air

By |2025-02-12T09:32:58+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Burning metals in air, Magnesium oxide. Heating metals in air, Magnesium oxide. ZIMSEC O Level Combined Science Notes: Experiment: Heating metals in air

Aim: To heat metals in air and observe and record the process and results

Materials: magnesium, zinc, iron, copper, tongs, burner

Method

  1. Exam the metals and take note of their appearance before heating […]
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Experiment: Investigating the gas produced by acids and carbonates

By |2025-02-12T09:04:28+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

ZIMSEC O Level Combined Science Notes: Experiment: Investigating the gas produced by acids and carbonates

Aim: To investigate the reaction of acids and carbonates and the gas that is produced

Materials: sodium corbonate/sodium hydrogen carbonate (baking soda), dilute hydrochloric acid/vinegar, lime water/ligted splint, 2 test tubes

Acids and carbonates react to release carbon dioxide Acids and carbonates […]

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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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