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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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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Experiment: Demonstrating the effects of short-circuits and overloads

By |2025-02-12T09:06:51+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Demonstrating how fuses work Demonstrating how fuses work ZIMSEC O Level Combined Science Notes: Experiment: Demonstrating the effects of short-circuits and overloads

Aim: To demonstrate the effect of a short circuit/overloading of a circuit on a fuse

Materials: 6 or 12 V battery, copper wires, fuse wire/steel wool strand, switch, car headlamp, torch bulb, switch, […]

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Metal and metal alloy properties and their construction uses

By |2025-02-12T09:21:53+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Metals are popular in construction. Image credit traveldigg.com Metals are popular in construction. Image credit traveldigg.com ZIMSEC O Level Combined Science Notes: Metal and metal alloy properties and their construction uses

  • Metals are popular construction materials
  • They have properties that make them suited for making diverse structures
  • They are ductile which means […]
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Machines: The inclined plane

By |2025-02-12T09:39:15+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

ZIMSEC O Level Combined Science Notes: Machines: The inclined plane

  • Is also known as a ramp
  • is a flat supporting surface tilted at an angle,
  • with one end higher than the other,
  • used as an aid for raising or lowering a load
  • Inclined planes are widely used to move heavy loads over vertical obstacles
  • examples vary from a […]
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Hydraulic brakes

By |2025-02-12T09:10:35+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Car brakes. Image driverside.com Car brakes. Image driverside.com ZIMSEC O Level Combined Science Notes: Hydraulic brakes

  • Is another example of hydraulic machines
  • Pressure is applied on the brake pedal using the car driver’s foot

Car brakes. Image credit dtzone.com Car brakes. Image credit dtzone.com […]

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Immunity and Immunisation

By |2025-02-12T09:28:55+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Sindiso Marume holding her brother's health card. Image credit irinnews.org Sindiso Marume holding her brother’s health card. Image credit irinnews.org ZIMSEC O Level Combined Science Notes: Disease:Immunity and Immunisation

  • Immunity-is the ability of the body to resist diseases
  • There are various types of immunity:
  • Antigen-is any substance that causes […]
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Contraception: Abstinence

By |2025-02-12T09:46:09+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Couple holding hands. Image credit neguswhoread.com Couple holding hands. Image credit neguswhoread.com ZIMSEC O Level Combined Science Notes:Contraception: Abstinence

  • It involves total avoidance of sexual intercourse

Adavantages

  • Many couples agree to wait until marriage
  • There is no risk of contracting  Sexually Transmitted Infections
  • It is 100% effective
  • It is supported by most religious […]
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