O Level Science Notes Archives - Free ZIMSEC & Cambridge Revision Notes

Mineral nutrition

By garikaib|2025-02-12T08:55:43+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Pottasium deficiency in maize. Image credit thompsonslimited.com Potassium deficiency in maize. Image credit thompsonslimited.com ZIMSEC O Level Combined Science Notes: Mineral Nutrition

Besides water and carbon dioxide plants also need many different mineral salts from their environment.
These mineral salts are required in small quantities.
They are taken up by the plant in […]

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Animal Parasites and diseases

By garikaib|2025-02-12T09:30:38+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Ticks on bull. Image credit morningagclips.com ZIMSEC O Level Combined Science Notes: Animal Parasites and diseases

Farmers in Zimbabwe typically raise goats, cattle, chickens and sheep.
Disease spread much more quickly where large numbers of the same type of livestock are kept close together when compared […]

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Transpiration in plants

By garikaib|2025-02-12T09:39:59+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Demostrating transpiration. Image credit masterwoodsman.com ZIMSEC O Level Combined Science Notes:Transpiration in plants

Water enters plant roots at all hours of the day.
Some trees absorb as much as 5 litres of water per minute.
Over 95% of the water that enters a plant through the roots exits […]

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The dispersal of plant seeds

By garikaib|2025-02-12T09:29:56+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Guava fruits are juicy and the seeds are can resist digestion. Image credit plantvillage.org ZIMSEC O Level Combined Science Notes: Reproduction in plants: Reproduction in Plants:The dispersal of plant seeds

The ovary may also become fleshy and […]

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Experiment: Finding soil organisms

By garikaib|2025-02-12T08:56:32+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Finding soil organisms. ZIMSEC O Level Combined Science Notes: Experiment: Finding soil organisms

Materials: digging tools, pen and paper, tweezers, gauze, beaker, filter tunnel, light bulb, clamp stand, microscope/hand lens, containers

Method

Go out and look for soil organisms. Look for things such as holes in the soil
Take soil samples
Set up […]

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Changes in state

By garikaib|2025-02-12T09:08:59+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Melting ice. Image credit flemox.com ZIMSEC O Level Combined Science Notes: Changes in state

When a solid item is heated the forces of attraction between the particles become weaker

as a result the particles move more quickly

The particles gain more kinetic energy
the solid item melts

[…]

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Deficiency Diseases

By garikaib|2025-02-12T09:16:24+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Iodised salt can prevent iodine deficiency ZIMSEC O Level Combined Science Notes: Deficiency Diseases

A person might suffer from a deficiency disease if their diet lacks certain essential minerals and vitamins
Two essential minerals and vitamins are:
Iodine and
Vitamins

Iodine Goitre is a [...]
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The reduction process
Gallery
The reduction process

Notes, O Level Science Notes, Ordinary Level Notes

The reduction process

By garikaib|2025-02-12T09:43:27+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

ZIMSEC O Level Combined Science Notes: The reduction process

Reduction is the opposite of oxidation
Reduction is the removal of oxygen from a substance/compound
It can also be the addition of oxygen

The reduction of copper. Image credit chemistrydemos.co.uk The reduction of copper.

A reducing agent removes oxygen or adds hydrogen
Metals cannot be […]

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The speed of reactions

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

Rate of reactions. Image credit about.com ZIMSEC O Level Combined Science Notes: The speed of reactions

Reactions happen at different speeds
This is because there are a number of factors that influence the speed of a reaction even between the same reagents
Reagents are […]

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