February 2025

The Manufacture of sulphuric acid

By |2025-02-12T08:56:03+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

ZIMSEC O Level Combined Science Notes: The production of sulphuric acid

  • Sulphuric acid is produced using the Contact process
  • In Zimbabwe there is a sulphuric acid production plant at Zimphos in Harare
  • Sulpher or iron pyrites (iron sulphide) is roasted to form sulphur dioxide
  • The word equation for roasting iron pyrites is:
  • \text{iron sulphide+oxygen}\rightarrow\text{iron oxide+sulpher dioxide}
  • The word […]
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Experiment:investigating fuel efficiency

By |2025-02-12T09:11:59+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Testing fuel to determine its energy content Testing fuel to determine its energy content ZIMSEC O Level Combined Science Notes: Experiment:investigating fuel efficiency

Aim: To determine the amount of heat liberated when different liquid fuels burn

Materials:  2 spirit burners, wooden block, clamp and stand, meths, paraffin, thermometer, draught shields, clamp, beaker, water, tripod […]

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Experiment: Finding the resistance of a resistor using a voltmeter

By |2025-02-12T09:26:37+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

ZIMSEC O Level Combined Science Notes:  Experiment: Finding the resistance of a resistor using a voltmeter

Aim:  To find the resistance of a resistor in a circuit using voltmeter

Materials: cells, ammeter, resistor,switch, leads with crocodile clips

Finding Resistance

Method

  1. Set up the circuit as shown above
  2. Close the switch
  3. Read and record values of the […]
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Introduction:Generators and Motors

By |2025-02-12T09:43:00+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Hwange Power Plant. Image credit chronicle.co.zw Hwange Power Plant. Image credit chronicle.co.zw ZIMSEC O Level Combined Science Notes: Introduction:Motors and generators

  • Due to their nature batteries and cells produce a limited amount of electrical power
  • A lot of the electricity used in homes and industries comes from generators
  • Generators convert kinetic […]
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Reinforced concrete and stone properties and structures

By |2025-02-12T09:22:52+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Reinforced concrete. Image credit surfcivil.blogspot.com Reinforced concrete. Image credit surfcivil.blogspot.com ZIMSEC O Level Combined Science Notes: Metal and metal alloy properties and their construction uses

  • Often building materials are combined when building a structure
  • The most common such mixture is reinforced concrete
  • It is a mixture of steel and concrete
  • Steel is […]
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Experiment:Finding the mechanical advantage of an inclined plane

By |2025-02-12T09:40:29+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

ZIMSEC O Level Combined Science Notes: Experiment:Finding the mechanical advantage of an inclined plane

Aim: Finding the Mechanical Advantage of an inclined plane

Materials: 1m long plank, sandpaper, bricks. cotton reel, nails, thick steel wire, wood block (smoothed on the underside) weights/tin and sand, pliers, string, spring balance/scales

Finding the mechanical of an inclined plane Finding the […]

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Experiment: To show how a hydraulic Machine increases force

By |2025-02-12T09:11:40+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Syringes showing how a hydraulic machine works Syringes showing how a hydraulic machine works ZIMSEC O Level Combined Science Notes: Experiment: To show how a hydraulic Machine increases force

Aim: To show how a hydraulic machine increases force

Materials:  small syringe, syringe with larger diameter, plastic tube, water, ruler

Method

  1. Half fill the large syringe […]
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Diseases:HIV/AIDS

By |2025-02-12T09:30:54+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Zimbabwe nurse and health worker. Image credit icrc.org Zimbabwe nurse and health worker. Image credit icrc.org ZIMSEC O Level Combined Science Notes: Disease:Immunity and Immunisation

HIV and Its effects

  • HIV stands for Human Immunodeficiency Virus
  • It lives in the body fluids including blood, saliva, semen, tears etc
  • It enters the body in […]
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Causes of infertility

By |2025-02-12T08:57:00+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Sterility can cause strain in a relationship. Image credit colossiansfamilynetwork.org Sterility can cause strain in a relationship. Image credit colossiansfamilynetwork.org ZIMSEC O Level Combined Science Notes: Causes of infertility

  • Sterility is the inability to reproduce
  • There are a number of causes for sterility
  • Low sperm count (makes it […]
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