Weather - Grade 7 Social Studies Revision Notes

• Weather
  • Elements Of Weather
• Factors to Consider when Siting a Weather Station
  • Constructing Selected Instruments For Measuring Elements Of Weather
  • Historical Information

Weather

Weather is the daily atmospheric conditions of a place at a particular time.

Elements Of Weather

1. Temperature
   
   • Measure or degree of hotness or coldness of a place
2. Humidity
   
   • The amount of water vapour or moisture in the atmosphere
3. Precipitation
   
   • All forms of moisture which fall from the atmosphere to the earth’s surface
   • Rainfall is a form of precipitation formed from clouds that in form of water droplets
4. Atmospheric pressure
5. Wind
   • Moving air on the surface of the earth
6. Sunshine
   • Direct rays of sunlight on the surface of the earth
7. Cloud cover
   • Mass of tiny droplets of water or ice formed through condensation

Analysis and interpretation of weather conditions

Diurnal/daily Temperature range
-Difference between the maximum and minimum temperature for any one day.

Mean Daily Temperature
-Average of the maximum and the minimum daily temperatures.

Mean Monthly temperature
-Sum of mean daily temperatures in a month divided by the number of days in that month.

Mean Monthly minimum Temperature
-Sum of daily minimum temperatures divided by the number of days in that month.

Mean Monthly Maximum Temperature
-Sum of daily maximum temperatures divided by the number of days in that month.

Mean Annual Temperature
-Sum of mean monthly temperatures divided by 12.

Mean Annual Temperature Range
-Difference between the highest and the lowest mean monthly temperatures in a year.

Monthly Rainfall Total
-Sum of rainfall recorded in a month.

Annual Rainfall Total
-Sum of monthly rainfall totals for 12 months.

Mean Monthly Rainfall
-Sum of rainfall totals for a particular month over several years divided by the number of the years of observation.

Mean Annual Rainfall
-Sum of mean monthly rainfall for 12 months of the year.

Factors To Consider When Siting A Weather Station

Weather Station

• A place where observation, measuring and recording of weather elements is done
  

Factors to Be Taken Into Account When Sitting a Weather Station

1. Open space
   
   • An open place where there is little obstruction of weather elements.
2. Accessible place
   
   • Accessible place so that recording can be done easily.
3. Gently sloping land
   
   • A fairly level or gently sloping ground (5◦) so that it’s easy to position weather instruments.
4. Security
   
   • The place should have security
5. The place should provide a wide view of the surrounding landscape and the sky.
6. The site should be free from flooding.

Constructing Selected Instruments For Measuring Elements Of Weather

Instruments for Measuring Elements of Weather

1. Thermometer- measures temperature
2. Hygrometer- measures humidity
3. Rain gauge-measures rainfall
4. Barometer-measures air pressure
5. Sunshine recorder-measures sunshine duration and intensity
6. Wind vane –measures wind direction
7. Anemometer-measures wind speed

1. Constructing a wind stock
   PUPIL’S ACTIVITY
   PAGE 52
   Materials needed
   1. A paper cup
   2. Clay and plasticine
   3. A pin
   4. Drinking straw
   5. Marker pen
   6. A white circular cardboard
   7. Square and triangular paper cuttings
   8. A pencil with a rubber head
      
2. Constructing a rain gauge
   PUPIL’S ACTIVITY
   PAGE 53
   Materials needed
   1. A 2-litre plastic bottle
   2. Ruler
   3. A ballpoint pen
   4. Masking tape
   5. A scalpel or pair of scissors
      
3. Constructing a Windsock
   PUPIL’S ACTIVITY
   PAGE 53-54
   Materials needed
   1. Cylindrical bag
   2. String
   3. A scalpel
   4. Water paints
   5. An empty plastic fat/magarine tin
   6. Masking tape or cellotape
   7. A pole with a pointed end
   8. Painting brushes or chewed sticks
      

Significance of weather to human

1. Helps us to be aware of natural calamities related to weather before they occur so as to take precautionary measures.
2. Guiding tourists on when to visit national parks.
3. Helps farmers to plan their activities such as planting, harvesting, etc.
4. Ensures air and water transport is carried out safely.
5. Helps sporting people to plan their training and competition schedules.
6. Helps people to plan many other activities such as mining, electricity generation, holiday events, etc.
7. Helps fishing communities to plan their activities

Historical Information

Sources of historical information in the society

1. Monuments
2. Caves
3. Historical pictures
4. Folk songs
5. Old coins
6. Recorded folk stories
7. Archaeological sites
8. Textbooks
9. Articles
10. Myths
11. Artefacts,
12. Fossils

Primary and secondary sources of information

Primary source is historical information that are created during the time period studied or were created at a later age by participant in even being practised
Secondary source is historical information that interprets or analyses a historical phenomenon

Ways of preserving historical information

Significance of historical information in providing evidence of past accounts