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

Plant pests and diseases

By garikaib|2022-09-15T12:41:52+02:00January 24th, 2023|Notes, O Level Science Notes, Ordinary Level Notes|

A grasshopper. Image credit nutrainigridients.com A grasshopper. Image credit nutrainigridients.com ZIMSEC O Level Combined Science Notes: Plant pests and diseases

In the wild there is a balance in nature.
The are few pests and diseases that destroy plants.
In crop plants there are more pests that cause and spread disease.
This is because there […]

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Inhaled vs Exhaled air experiment: Method 1

By garikaib|2022-09-15T12:41:44+02:00January 24th, 2023|Notes, O Level Science Notes, Ordinary Level Notes|

Image credit vimeo.com ZIMSEC O Level Combined Science Notes: Inhaled vs Exhaled air experiment: Method 1

Aim: Comparing the inhaled and exhaled air.

Materials: large transparent container (e.g. bell jar), candle, tin lid, water, large basin, rubber tubing, ruler.

Method

exhaled_inhaled_air-min

Place the large […]

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Health and well being

By garikaib|2022-09-15T12:40:41+02:00January 24th, 2023|Notes, O Level Science Notes, Ordinary Level Notes|

Exercise is key to maintaining one’es health. Image credit centrictv.com ZIMSEC O Level Combined Science Notes: Health and well being

Health is the absence of disease
It is a state of being physically and psychologically well.
A person is said to be healthy […]

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Asexual reproduction

By garikaib|2022-09-15T12:40:32+02:00January 24th, 2023|Notes, O Level Science Notes, Ordinary Level Notes|

A bud on a sugarcane cutting. Image credit 10degreesabove.com ZIMSEC O Level Combined Science Notes: Reproduction in plants: Asexual reproduction/ Vegetative reproduction

Is also known as asexual reproduction
This takes place when plants reproduce without producing seeds
Such plants have modified stems, roots or […]

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Variation

By garikaib|2022-09-15T12:40:23+02:00January 24th, 2023|Notes, O Level Science Notes, Ordinary Level Notes|

Variation in chillies. Image credit chilipapryczka.pl ZIMSEC O Level Combined Science Notes: Variation

The living world has many thousands of different types of plants and animals
For example lions are different from hyenas which in turn are different from say goats
In plants the Msasa trees are […]

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Experiment: to show that solids change shape when they melt

By garikaib|2022-09-15T12:40:14+02:00January 24th, 2023|Notes, O Level Science Notes, Ordinary Level Notes|

Melting wax takes up the shape of the container. Image credit about.com ZIMSEC O Level Combined Science Notes: An experiment to show that solids change shape when they melt

Materials: tin lid/evapouration dish, burner, burner stand, candle wax

Method

place […]

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Chemical Reactions
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Chemical Reactions

Notes, O Level Science Notes, Ordinary Level Notes

Chemical Reactions

By garikaib|2022-09-15T12:39:46+02:00January 24th, 2023|Notes, O Level Science Notes, Ordinary Level Notes|

ZIMSEC O Level Combined Science Notes: Chemical Reactions

Introduction to reactions

A compound is formed when a chemical reaction takes place
Chemical change takes place to form the compound
Word equations can be used as a short hand way to show what has happened
An example of a chemical equation is:
\text{iron + sulpher}\rightarrow \text{iron sulphide}
As already […]

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Experiment: Reducing Iron oxide using aluminium
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Experiment: Reducing Iron oxide using aluminium

Notes, O Level Science Notes, Ordinary Level Notes

Experiment: Reducing Iron oxide using aluminium

By garikaib|2022-09-15T12:39:33+02:00January 24th, 2023|Notes, O Level Science Notes, Ordinary Level Notes|

ZIMSEC O Level Combined Science Notes: Experiment: Reducing Iron oxide using aluminium

Aim: To remove oxygen from iron oxide using aluminum

Materials: sand, tin can, safety screen, magnesium ribbon and magnesium powder, wooden splint, aluminum powder, dry iron oxide, barium preoxide

Reducing iron oxide using aluminum oxide

Method

Fill the tin […]

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Experiment: Investigating the effects of concentration on marble chips

By garikaib|2022-09-15T12:39:25+02:00January 24th, 2023|Notes, O Level Science Notes, Ordinary Level Notes|

Concentration varies directly with the rate of reaction ZIMSEC O Level Combined Science Notes: Experiment: Investigating the effects of concentration on marble chips