Pit latrine
Pit Latrine. Image credit sswm.info ZIMSEC O Level Combined Science Notes: Pit Latrine
- It consists of a deep hole in the ground into which all human urine and faeces (excrement) are deposited
A pit latrine
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February 2025
Photosynthesis
ZIMSEC O Level Combined Science: Photosynthesis
- Green plants are the food and oxygen producers of the living world.
- They manufacture organic molecules from inorganic raw materials.
- Animals rely on green plants to make food that provides them with energy and oxygen.
- Green plants are thus known as producers and animals are in turn known as consumers.
- Only green plants […]
Digestive systems of cows and rabbits
Cows. Image credit creativeblogs.net ZIMSEC O Level Combined Science Notes: Digestive systems of cows and rabbits
- Cows and rabbits are examples of herbivores.
- They feed on plants e.g. grass and leaves.
- Pant structures contain a large amount of cellulose which cannot be digested easily.
- Cellulose is a fibrous carbohydrate.
- Much […]
Plant transport and the structure of plants
Tomato Plant. image credit wisegeek.com ZIMSEC O Level Combined Science Notes: Plant transport and the structure of plants
- Plants have two main organ systems: a shoot system and a root system
Tomato plant structure. Image credit […]
The mammal heart
The structure of the human heart. ZIMSEC O Level Combined Science Notes: The mammal heart
- Is made up of muscle which contracts continuously throughout the mammal’s life.
- The number of contractions differ from mammal to mammal
- In elephants it contracts about 25 times/minute
- In humans it contracts about 70-80 […]
Experiment comparing the particle size of soils
Soil sedimentation test. ZIMSEC O Level Combined Science Notes: Experiment comparing the particle size of soils
Materials: samples of sandy, loamy and clay soils, 3 measuring cylinders/tall transparent containers, water
Method
- Place sample of each soil sample into a tall container to about a quarter of its height
- Add water to until […]
Artificial Ecosystems
A maize field is an example of an artificial ecosystems. Image wordpress.com ZIMSEC O Level Combined Science Notes: Artificial Ecosystems
- An artificial ecosystem is one that is heavily influenced by human activities
- The practice of mono-culture, crop production and the […]
An introduction to Beams and their types
Common types of beams and their associated forces ZIMSEC O Level Combined Science Notes: An introduction to Beams and their types
- A beam is any material that is supported so that it can hold a load
- A simple beam is a length of material e.g steel supported along its length so that […]
Experiment: Heating metals in air
Heating metals in air, Magnesium oxide. ZIMSEC O Level Combined Science Notes: Experiment: Heating metals in air
Aim: To heat metals in air and observe and record the process and results
Materials: magnesium, zinc, iron, copper, tongs, burner
Method
- Exam the metals and take note of their appearance before heating […]
Experiment: Investigating the gas produced by acids and carbonates
ZIMSEC O Level Combined Science Notes: Experiment: Investigating the gas produced by acids and carbonates
Aim: To investigate the reaction of acids and carbonates and the gas that is produced
Materials: sodium corbonate/sodium hydrogen carbonate (baking soda), dilute hydrochloric acid/vinegar, lime water/ligted splint, 2 test tubes
Acids and carbonates […]