February 2025

Uses of sulphuric acid

By |2025-02-12T09:43:37+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

ZIMSEC O Level Combined Science Notes: Uses of sulphuric acid

  • Most of the sulphuric acid produced at Zimphos is used to
  • make fertilizers (mostly superphoshate)
  •  Some of the sulphiric acid is used to  manufacture aluminum sulphate
  • Which in turn is used as a flocculent in water purification processes
  • Bauxite from Mutare is dissolved into sulphuric acid
  • The word […]
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Experiment: Demonstrating that carbon dioxide extinguishes a burning flame

By |2025-02-12T09:10:46+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Carbon dioxide extinguishes flames Carbon dioxide extinguishes flames ZIMSEC O Level Combined Science Notes: Experiment: Demonstrating that carbon dioxide extinguishes a burning flame

Aim: to show that carbon dioxide extinguishes a flame

Materials:  3 different sized candles, vinegar, baking soda, beaker or plastic bottle, shallow dish

Method

  1. Place the 3 pieces of candle in a […]
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Experiment: Current and Voltage

By |2025-02-12T09:24:45+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

ZIMSEC O Level Combined Science Notes: Experiment: Current and Voltage 

Aim: To show how current changes with voltage and to find the resistance of a resistor

Materials: Three/Four 1.5V battery cells, ammeter, lamp,resistor, switch, leads with crocodile clips

Method

 

Current and Voltage Current and Voltage

  1. Set up the series using one cell as shown in the […]
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The Ampere-Hour

By |2025-02-12T09:41:23+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

ZIMSEC O Level Combined Science Notes: The Ampere-Hour

  • It is used to measure the current capacity of cells and batteries
  • is the amount of energy charge in a battery/cell that will allow one ampere of current to flow for one hour
  • It is thus a unit of measuring a cell/battery’s charge
  • For example if a battery is rated as […]
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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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Machines: Pulleys

By |2025-02-12T09:41:07+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Wooden pulleys. Image credit wisegeek.com Wooden pulleys. Image credit wisegeek.com ZIMSEC O Level Combined Science Notes: Machines: Pulleys

  • A pulley is a basic device or machine made of a wheel with a rim that a chain/cord/rope fits around
  • A single fixed pulley as shown below is used to change the direction […]
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Teeth and tooth decay

By |2025-02-12T09:16:38+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Good dental care is part of human health. Image credit claimfame.com Good dental care is part of human health. Image credit claimfame.com ZIMSEC O Level Combined Science Notes: Teeth and tooth decay

  • While people enjoy food of all varieties
  • Some types of food
  • For example sweets, chocolates, carbonated drinks, cakes and […]
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The menstrual cycle

By |2025-02-12T09:34:10+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Image credit lifestylechallenge.deborahgabriel.com Image credit lifestylechallenge.deborahgabriel.com ZIMSEC O Level Combined Science Notes: The menstrual cycle

  • The reproductive cycle in females is called the menstrual/estrus cycle
  • It has an average of 28 days
  • It varies from individual to individual but it follows a set pattern
  • The cycle is regulated by hormones produced […]
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Waste disposal

By |2025-02-12T09:01:40+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Waste disposal in Harare. Image credit thezimbabwedaily.com Waste disposal in Harare. Image credit thezimbabwedaily.com ZIMSEC O Level Combined Science Notes: Waste disposal

  • Several terms are used when dealing with waste
  • Sewage-is the name given to human excrement (faeces and urine) when collected together.
  • Sewage also includes kitchen waste and industrial waste

    • […]

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