February 2025

Fuel efficiency

By |2025-02-12T09:11:15+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

ZIMSEC O Level Combined Science Notes: Fuel efficiency

  • Fuel efficiency measures the amount of energy that can be obtained from a given quantity of fuel
  • It is often useful to know which fuel gives the most energy(heat) per given unit
  • In a laboratory fuel efficiency can be determined by measuring the temperature rise of water when it is […]
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Ohm’s Law

By |2025-02-12T09:25:59+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

ZIMSEC O Level Combined Science Notes: Experiment: Ohm’s Law

  • It gives the relationship between potential difference and current through a wire in a circuit
  • According to the law:
  • \text{potential difference}\propto\text{current}
  • The current passing through a wire is proportional to the potential difference across its ends
  • Provided the temperature remains constant
  • An equation can thus be formed:
  • constant\dfrac{\text{potential difference(V)}}{\text{current […]
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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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Demonstrating compression and tensile forces

By |2025-02-12T09:08:17+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Demonstrating tension and compression forces Demonstrating tension and compression forces ZIMSEC O Level Combined Science Notes: Experiment: Demonstrating compression and tensile forces

Aim:  To demonstrate compression and tensional(stretching forces)

Materials: glue, tissue paper, rubber, two small blocks of wood, plastic ruler/rubber hose

Method Demonstrating tension and compression forces. Image credit MediaWiki

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Factors to consider when choosing construction materials

By |2025-02-12T09:23:47+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

A house built using Eco friendly materials. Image credit asiagreenbuildings.com A house built using Eco friendly materials. Image credit asiagreenbuildings.com ZIMSEC O Level Combined Science Notes: Factors to consider when choosing construction materials

  • The choice of building material depends mainly on the properties of the materials and
  • The purpose of the […]
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Experiment:Lifting weights using pulleys

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

Testing pulleys using a test meter Testing pulleys using a test meter ZIMSEC O Level Combined Science Notes: Experiment:Lifting weights using pulleys

Aim: To use pulleys to lift loads

Materials:  4 single pulleys, string, 1kg mass/a tin filled with sand, spring balance, clamp stand, meter rule

Method

  1. Set up a fixed pulley as shown above
  2. […]

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Experiment: Testing tooth cleaning agent

By |2025-02-12T09:17:52+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Colgate toothpaste Colgate toothpaste ZIMSEC O Level Combined Science Notes: Experiment: Testing tooth cleaning agent

Aim: To test the properties of teeth cleaning agents

Materials: various brands of toothpaste, pH paper, microscopes, slat, bicarbonate of soda, lid bottles/suitable containers for the toothpaste

Method

  1. Examine toothpaste under a microscope to compare the particle size of the various […]
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Pregnancy

By |2025-02-12T09:35:40+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

ZIMSEC O Level Combined Science Notes: Pregnancy

  • The vagina receives an erect penis during sexual intercourse
  • During sexual intercourse, sperms are ejaculated into the vagina
  • There they begin to swim up to the oviducts
  • If an ovum is released at this time it may be fertilised in the oviduct
  • Although many sperms reach the ovum only one will […]
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