February 2025

Diffusion and Osmosis experiments: Visking Tubing/Egg membrane

By |2025-02-12T09:05:48+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

A person tying the visking tubing. Image credit YouTube. A person tying the visking tubing. Image credit YouTube. ZIMSEC O Level Combined Science Notes:Diffusion and Osmosis experiments

Aim: Create a membrane model for molecules and their movement.

Materials

Visking tubing/egg membrane, string, beaker, 20% sugar solution, weighing balance, water.

Method A

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Examining adaptations of flowers to pollination

By |2025-02-12T09:25:46+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

A bird pollinating a flower. Image credit gilligalloubird.com A bird pollinating a flower. Image credit gilligalloubird.com ZIMSEC O Level Combined Science Notes: Reproduction in plants: Examining adaptations of flowers to pollination

Materials: maize(male and female) or any type of grass flowers, bean flowers or any insect pollinated flowers, hand lenses, microscope slides, […]

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Experiment: Testing the infiltration capacity of soils

By |2025-02-12T09:44:29+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Testing infiltration in soils Testing infiltration in soils ZIMSEC O Level Combined Science Notes: Testing the infiltration capacity of soils

Materials: Tins with their tops and bottoms removed, water

Method

  1. Gently push the tins into the ground, make sure that they are in different soil types
  2. Pour 100ml of water into the cylinders and measure […]
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Isotopes and the importance of proton numbers

By |2025-02-12T09:06:50+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

The three isotopes of hydrogen. Image credit wikipedia.org The three isotopes of hydrogen. Image credit MediaWiki ZIMSEC O Level Combined Science Notes: Isotopes and the importance of proton numbers

  • The electron orbits of these two elements is small and can only carry two electrons
  • The next element in the series is lithium
  • It comes […]
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Predicting reactions of a metal using the reactivity series

By |2025-02-12T09:40:26+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

The reactivity series. Image credit wordpress.com The reactivity series. Image credit wordpress.com ZIMSEC O Level Combined Science Notes: Experiment: Predicting reactions of a metal using the reactivity series

  • Metals do not react with water and air at the same rate
  • The rate at which they react differs from metal to metal
  • Some metals […]
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Neutralisation/Salts

By |2025-02-12T09:10:01+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

ZIMSEC O Level Combined Science Notes: Neutralisation/Salts

  • The acidity and alkalinity of a solution can be represented on the pH scale
  • If the pH is low i.e less than 7 then the solution is acidic
  • If the pH is high i.e higher than 7 then the solution is alkaline
  • If a solution has a pH of 7 […]
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Extraction of copper from sulphides

By |2025-02-12T09:26:36+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

ZIMSEC O Level Combined Science Notes:Extraction of copper from sulphides

  • Copper is extracted from various types of ore including sulphide ores
  • For example copper ores found on the Great Dyke near Mhangura is of the sulphide type
  • Once the sulphide ore is extracted from the earth
  • It is crushed to form a very fine powder which is then further […]
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Liquification of air

By |2025-02-12T09:40:17+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Sable chemicals plant. Image credit zimeye.net Sable chemicals plant. Image credit zimeye.net ZIMSEC O Level Combined Science Notes: Liquification of air

  • In Zimbabwe the air liquification plant is at Sable Chemicals
  • Two main components of air are separated:
  • Nitrogen and Oxygen
  • These two gases are used in either liquid or gas form

    • […]

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Ethanol as a source of energy

By |2025-02-12T09:07:30+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

ZIMSEC O Level Combined Science Notes: Ethanol as a source of energy

  • Ethanol is also known as alcohol
  • It is made by fermenting plants with a high sugar content
  • Sugar cane is commonly used to make ethanol in Zimbabwe
  • The plant is grown in Zimbabwe’s Lowveld
  • Water from Mutirikwe and Bangala Dams is used to irrigate the crop
  • Biomas is […]
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