February 2025

The physical components of the soil

By |2025-02-12T09:40:16+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Loam soil. Image credit betterground.org Loam soil. Image credit betterground.org ZIMSEC O Level Combined Science Notes: The physical components of the soil  

  • Soil is made up of rock/soil particles
  • Some soils are easy to compress because they have air in them
  • Soils are usually moist
  • Soils also have dissolved minerals in them

Sand, Loam and […]

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The nitrogen cycle

By |2025-02-12T09:03:20+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Nitrogen fixing roots in legumes. Image credit MediaWiki Nitrogen fixing roots in legumes. Image credit MediaWiki ZIMSEC O Level Combined Science Notes: The nitrogen cycle

  • Nitrogen makes up 79% of the atmosphere
  • Animals cannot absorb Nitrogen as a gas
  • They absorb it indirectly usually as part of food
  • Recycling of nitrogen is carried out […]
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Experiment: the cooling curve of naphthalene

By |2025-02-12T09:14:24+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Cooling naphthalene Cooling naphthalene ZIMSEC O Level Combined Science Notes: Experiment: the cooling curve of naphthalene

Materials: test tube, naphthalene, thermometer, hot water, burner, stand, clamp

Be careful as naphthalene vapour is poisonous: you can wear a breathing mask to reduce the risk of you inhaling the vapour

Method

  1. Fill a test tube with naphthalene until […]
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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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Experiment: The corrosion of metals by acids

By |2025-02-12T09:02:23+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

ZIMSEC O Level Combined Science Notes: Experiment: The corrosion of metals by acids

Aim: Investigating the corrosion of some metals by acids

The corrosion of metals by acid gives off hydrogen gas The corrosion of metals by acid gives off hydrogen gas

Materials: 5 test tubes, dilute hydrochloric acid, granulated zinc, iron fillings/iron nail, copper foil, […]

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Experiment: Nickel plating a piece of copper sheet

By |2025-02-12T09:34:35+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Nickel plating copper Nickel plating copper ZIMSEC O Level Combined Science Notes:  Experiment: Nickel platting a piece of copper sheet

Aim: To nickel plate a piece of copper

Materials: beaker, nickel sulphate, boric acid, burner, nickel electrode, 1.5 v cell, copper electrode/copper plated item, universal indicator

Method

  1. In a beaker make 20cm3 a solution using 54g […]
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Experiment: Burning fuels

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

Burning Fuels Burning Fuels ZIMSEC O Level Combined Science Notes: Experiment: Burning fuels

Aim: To burn and investigate the nature of fuels

Materials: methylated spirits/alcohol, candle, meths burner, bunsen burner, paraffin, tin lid or porcelain dish, tongs

Method

  1. Light a meths burner and observe the flame
  2. Burn a small amount of alcohol on a tine lid, […]
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Electric cells: Introduction

By |2025-02-12T09:33:41+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Duracell electric cells. Image credit linkedin.com Duracell electric cells. Image credit linkedin.com ZIMSEC O Level Combined Science Notes: Introduction to electric cells

  • An electric cell converts chemical energy into electrical energy
  • Two metal electrodes are dipped into an electrolyte
  • During the chemical reaction that takes place in the cell
  • One electrode […]
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