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

Chlorophyll and Photosynthesis

By garikaib|2025-02-12T09:41:18+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

A green leaf. Image credit wallconvert.com ZIMSEC O Level Combined Science: Chlorophyll and Photosynthesis

Aim: To test whether chlorophyll is necessary for photosynthesis.

Materials

Two plants with variegated leaves i.e. leaves that are partly green, permanent marker and equipment for the start test. A [...]
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The enzyme amylase

By garikaib|2025-02-12T09:29:26+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Starch food. Image credit eurofins.com ZIMSEC O Level Combined Science Notes: The enzyme amylase

Energy in cells is obtained by breaking down food molecules during the respiration process.
The chemical reactions involved are carried out by enzymes.
Enzyme molecules also break down food molecules in the digestive system and […]

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Experiment: Testing for osmosis in living plants

By garikaib|2025-02-12T09:37:52+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Peeled potatoes. Image credit alsalamgroup.com ZIMSEC O Level Science Notes: Experiment: Testing osmosis in living plant tissue

Materials: potatoes, knife or blade, distilled water, sugar or salt, three containers,weighing balance.

Method

osmosis_plants

Prepare three pieces of peeled potato. Each block must be […]

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The differences between wind and insect pollinated flowers

By garikaib|2025-02-12T09:26:15+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Maize flower close up. image credit freeimagescollection.com ZIMSEC O Level Combined Science Notes: Reproduction in plants: The differences between wind and insect pollinated flowers

Not all flowers are exactly the same
Some flowers have adapted to be pollinated by wind
Others have adapted in a way […]

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Experiment: Testing the alkalinity/acidity of the soil

By garikaib|2025-02-12T09:45:43+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Testing the PH of soil. Image credit blogspot.com ZIMSEC O Level Combined Science Notes: Testing the alkalinity/acidity of the soil

Materials: Universal indicator/PH paper/PH Test meter, distilled water, test tubes, soil samples

Method

Place the soil samples into test tubes to a height of about […]

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Molecules

By garikaib|2025-02-12T09:07:27+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Molecules of carbon, oxygen, hydrogen and water ZIMSEC O Level Combined Science Notes: Molecules

A molecule is the smallest particle of a compound formed when atoms of elements combines
The atoms combine together by forming bonds
When these bonds are formed there are energy changes
Typically heat energy […]

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The strength of Materials

By garikaib|2025-02-12T09:14:47+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Different materials have different strength. Image credit wisegeek.com ZIMSEC O Level Combined Science Notes: The strength of Materials

A beam should be made of stronger material so that it can support a greater load
Different materials have different strength
Some material is greater when put […]

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Experiment: The reaction of metals with dilute Hydrochloric acid

By garikaib|2025-02-12T09:41:04+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Copper does not react with hydrochloric acid. Image credit fphoto.com ZIMSEC O Level Combined Science Notes: Experiment: The reaction of metals with dilute Hydrochloric acid

Aim: To examine the reactivity of metals with dilute hydrochloric acid

Materials: 5 test tubes, dilute hydrochloric acid, magnesium, zinc, […]

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Experiment: Investigating the neutralisation process
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Experiment: Investigating the neutralisation process

Notes, O Level Science Notes, Ordinary Level Notes

Experiment: Investigating the neutralisation process

By garikaib|2025-02-12T09:10:28+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

ZIMSEC O Level Combined Science Notes: Experiment: Investigating the neutralisation process

Aim: To find out what happens to the pH of an acid when a base is added

Materials: vinegar, plastic beaker, measuring cylinder, stirring rod, spatula/plastic teaspoon, slaked lime (calcium hydroxide), universal indicator paper

Method