February 2025

Immunity and Immunisation

By |2025-02-12T09:28:55+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Sindiso Marume holding her brother's health card. Image credit irinnews.org Sindiso Marume holding her brother’s health card. Image credit irinnews.org ZIMSEC O Level Combined Science Notes: Disease:Immunity and Immunisation

  • Immunity-is the ability of the body to resist diseases
  • There are various types of immunity:
  • Antigen-is any substance that causes […]
Read More
Comments Off on Immunity and Immunisation

Contraception: Abstinence

By |2025-02-12T09:46:09+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Couple holding hands. Image credit neguswhoread.com Couple holding hands. Image credit neguswhoread.com ZIMSEC O Level Combined Science Notes:Contraception: Abstinence

  • It involves total avoidance of sexual intercourse

Adavantages

  • Many couples agree to wait until marriage
  • There is no risk of contracting  Sexually Transmitted Infections
  • It is 100% effective
  • It is supported by most religious […]
Read More
Comments Off on Contraception: Abstinence

Inhaled vs Exhaled air experiment: Method 1

By |2025-02-12T09:37:32+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Image credit vimeo.com 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

  1. Place the large […]
Read More
Comments Off on Inhaled vs Exhaled air experiment: Method 1

Asexual reproduction

By |2025-02-12T09:34:33+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

A bud on a sugarcane cutting. Image credit 10degreesabove.com 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 […]
Read More
Comments Off on Asexual reproduction

Variation

By |2025-02-12T08:59:05+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Variation in chillies. Image credit chilipapryczka.pl 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 […]
Read More
Comments Off on Variation

Experiment: to show that solids change shape when they melt

By |2025-02-12T09:11:07+02:00February 12th, 2025|Notes, O Level Science Notes, Ordinary Level Notes|

Melting wax takes up the shape of the container. Image credit about.com 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

  1. place […]
Read More
Comments Off on Experiment: to show that solids change shape when they melt

Chemical Reactions

By |2025-02-12T09:19:25+02:00February 12th, 2025|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 […]
Read More
Comments Off on Chemical Reactions

Experiment: Reducing Iron oxide using aluminium

By |2025-02-12T08:56:02+02:00February 12th, 2025|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 Reducing iron oxide using aluminum oxide

Method

  1. Fill the tin […]
Read More
Comments Off on Experiment: Reducing Iron oxide using aluminium
Toggle Sliding Bar Area
Go to Top