January 2023
An aneroid barometer. Image Deliberate Changes to weather: Cloud seeding, Dam construction, Greenhouses
Greenhouses are used to grow crops like tomatoes in areas that suffer from frost or during winter. Image via Sustainablenantucket. ZIMSEC O Level Geography Notes: People and Weather: Deliberate Changes
Greenhouses
- These are used […]
Clouds
Clouds. Image by ThirdScribe. ZIMSEC O Level Geography Notes: Clouds
Refers to the fraction of the sky obscured by clouds when observed from a particular location. Okta is the usual unit of measurement of the cloud cover. Sky conditions are estimated in terms of how many eighths of the […]
Unintentional changes to weather
ZIMSEC O Level Geography Notes: People and Weather: Accidental Changes
Acid Rain
- The smoke from burning fuels and chemical industries rises into the air and mixes with water vapour.
- When the rain falls down it becomes acidic.
- The acid rain is a weak acid made up of sulphuric and nitric acids.
- Over, a long time (years for example), the rain […]
Wind direction and speed
A cup anemometer and windvane. Image by Noaa.gov. ZIMSEC O Level Geography Notes: Wind direction and speed.
Wind is the movement of air across the earth’s surface due to differences in pressure between two regions. Air moves from high pressure regions to low […]
Urban Heat Islands
Urban Heat Island. The diagram shows typical temperature differences between an Urban area and the adjacent rural area. Image via Pixshark.
ZIMSEC O Level Geography Notes: Urban Heat Islands.
- Due […]
Sunshine
A sunshine recorder. Image by Rfuess-Mueller. ZIMSEC O Level Geography Notes: Sunshine
- It has a glass sphere surrounded by a metal frame.
- On the frame is attached a sensitive card.
- The sphere focuses the sun’s rays onto the card.
- As the sun moves across the sky it burns […]
Weather Hazards
Floods are just one of many natural weather hazards. Image by The Australian. ZIMSEC O Level Geography Notes: Weather Hazards
- Weather hazards are conditions which are unfavorable to people and their activities that result from weather phenomena.
- There are […]
Land and sea breeze pressure system
Land and Sea breezes occur along coastal areas such as beaches. Image by Livescience. ZIMSEC O Level Geography Notes:Land and Sea breezes
- As the name clearly suggests these breezes occur along coastal areas or along large lakes […]
Lightining
Lightining. Image by GreenSociety. ZIMSEC O Level Geography Notes: Weather Hazards: Lightining
- Is typically caused by the physical characteristics of cumulonimbus weather conditions.
- As rain drops fall the energy which they have causes a positive charge to develop at the top of a cloud and negative charges to develop […]