O Level Science Notes Archives - Page 19 of 33 - Free ZIMSEC & Cambridge Revision Notes

Experiment: Comparing the strength of natural timber and other construction materials

By garikaib|2022-09-15T12:38:20+02:00January 24th, 2023|Notes, O Level Science Notes, Ordinary Level Notes|

Comparing the strength of various materials ZIMSEC O Level Combined Science Notes: Experiment: Comparing the strength of natural timber and other construction materials

Aim: To compare the strength of some natural timbers and other materials

Materials: Plywood, hard wood cut across the grain, soft wood cut along the grain, […]

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Experiment:Lifting weights using pulleys

By garikaib|2022-09-15T12:38:13+02:00January 24th, 2023|Notes, O Level Science Notes, Ordinary Level Notes|

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

Set up a fixed pulley as shown above

[…]

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People and Energy

By garikaib|2022-09-15T12:38:06+02:00January 24th, 2023|Notes, O Level Science Notes, Ordinary Level Notes|

Construction workers require a lot of energy. Image credit nehandaradio.com ZIMSEC O Level Combined Science Notes: Experiment: People and Energy

While it is true that everyone needs energy for metabolism and daily activities
Different people have different food needs
Food requirements can […]

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Male Reproductive system

By garikaib|2022-09-15T12:37:55+02:00January 24th, 2023|Notes, O Level Science Notes, Ordinary Level Notes|

Image credit raanetwork.org ZIMSEC O Level Combined Science Notes: Male Reproductive system

The diagram below shows the reproductive system of a man

Male reproductive system. Image credit goldiesroom.org

Testes-this is where sperms are made.

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Population Dynamics

By garikaib|2022-09-15T12:37:48+02:00January 24th, 2023|Notes, O Level Science Notes, Ordinary Level Notes|

Image credit idealscounseling.org

Image credit idealscounseling.orgZIMSEC O Level Combined Science Notes: Population Dynamics

Population-all the inhabitants of a particular place/area at one given time
The study of changes in population is known as demograph

Factors affecting population change

The birth rate-the number of live births per 1000 people per year.
Death/Mortality rate-is the number of […]

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Pesticide Warning Symbols

By garikaib|2022-09-15T12:41:51+02:00January 24th, 2023|Notes, O Level Science Notes, Ordinary Level Notes|

Image credit incomdirect.com ZIMSEC O Level Combined Science Notes: Pesticide Warning Symbols

Pesticides are graded according to their toxicity i.e.
According to how harmful they are to humans.
Every pesticide must have a label that clearly shows its “danger” level show.
There are four common danger levels of chemicals.

Purple […]

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Exhaled air vs inhaled air

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

Air sacs. Image credit MediaWiki ZIMSEC O Level Combined Science Notes:Exhaled air vs inhaled air

Air which enters the lungs (inhaled air) is different in several regards to air that is passed out (exhaled air)
Exhaled air contains less oxygen and more carbon dioxide.
It is also warmer […]

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Carrying out Food Tests

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

Testing for starch. Image credit fineartamerica.com ZIMSEC O Level Combined Science Notes: Carrying out Food Tests

It is important to know how much nutrients they contain
This would be useful to nutritionist and those who are health conscious

Food Testing experiments

Simple tests can be made […]

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Science: Ecosystems

By garikaib|2022-09-15T12:40:30+02:00January 24th, 2023|Notes, O Level Science Notes, Ordinary Level Notes|

An ecosystem diagram. Image credit ck12.org ZIMSEC O Level Combined Science Notes: Ecosystems

Is a self-contained system of interdependent organisms and their physical environment
An ecosystem can also be defined as a biological community of interacting organisms and their physical environment.
In an ecosystem a community of living […]

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Natural Ecosystems

By garikaib|2022-09-15T12:40:22+02:00January 24th, 2023|Notes, O Level Science Notes, Ordinary Level Notes|

Impala ecosystem Natural ecosystem. Image credit wordpress.com ZIMSEC O Level Combined Science Notes: Natural Ecosystems

In a natural ecosystem there is close interaction between the plants and animals
The green plants are the producers
The animals are the consumers
There are several levels of consumers
Primary consumers-these eat plants directly
They are also known as herbivores
Secondary […]

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January 2023