February 2025
Generators have many uses.Image credit wheelerdealers.co.zw ZIMSEC O Level Combined Science Notes: Uses of generators Introduction to Trusses
Roof trusses. Image credit myrooff.com ZIMSEC O Level Combined Science Notes: Introduction to Trusses
- A truss is a supporting framework for a roof, bridge or any other large structure
- Box and rectangular truss frameworks are inherently weak and susceptible to shear force
Experiment: To compare the resistance of different woods to termite attack
Treated poles. Image credit lynnridgetimbers.co.za ZIMSEC O Level Combined Science Notes: Experiment: To compare the resistance of different woods to termite attack
Aim: To compare the resistance of different types of wood to termite attack
Materials: gloss paint, used motor oil, creosote, 4 samples of softwood (pine), 4 samples of […]
The concept of pressure
- Pressure is the force acting over an area
- In such pressure is usually the force per unit area exerted by a fluid/gas
- over a surface with which it is in contact
- \text{Pressure=} \dfrac{Force}{Area}
- If a big force is exerted over a small area it results high pressure
- An example […]
Experiment: Finding conditions necessary for growth of microorganisms
Mouldy bread and their conditions. Image credit wordpress.com ZIMSEC O Level Combined Science Notes: Experiment: Finding conditions necessary for growth of microorganisms
Aim: To determine factors affecting the growth of microorganisms in food
Materials: 3 containers with sterilized lids, brad, milk, burners, drying agent (calcium chloride)
Method
- Pour […]
Contraception:Ways to prevent pregnancy
There are several major methods of contraception. Image credit relationshipplaybook.com ZIMSEC O Level Combined Science Notes:Contraception:Ways to prevent pregnancy
- Contraception-the deliberate use of artificial methods or other techniques to prevent pregnancy as a consequence of sexual intercourse
- Common methods of contraception […]
Blair toilet
Blair Toilet. Image credit thestandard.co.zw ZIMSEC O Level Combined Science Notes: Blair toilet
- This was developed by the Blair Research Laboratory
The Blair Toilet.
- It is a refinement of the pit latrine
- They use […]
Hourly rate/Time rate
Teachers receive a time rate pay. Image credit atlantablackstar.comZIMSEC O Level Business Studies Notes: Hourly rate/Time rate
- This is a way of paying workers based on the time/hours spent working
- The number of hours is calculated by multiplying a pre-agreed rate with the […]
Delegation
Delegation. Image credit blackenterprise.com
ZIMSEC O Level Business Studies Notes: Delegation
- Delegation-is the transfer of authority and responsibility by a superior/manager to a subordinate
- to carry out specific function,duties and tasks
- The delegator remains accountable for the outcome of the delegated work
- Delegation results in decentralisation
[…]
Written Communication
Written Communication. Image credit theodysseyonline.com
ZIMSEC O Level Business Studies Notes: Written Communication
- Involves any type of message that involves the use of the written word
- It includes things like emails, reports, letters, instant messages (Whatsapp and Facebook)
Advantages
- Same message can be delivered to different receives with speed e.g. an […]