How to Use This Page
Attempt each question on your own first, then compare with the solutions below. Understanding the reasoning is more important than memorising the answer. Use the Key Concepts table for quick revision before your exam.
Key Concepts (Quick Recap)
| Term | Definition |
|---|---|
| Weather | Day-to-day condition of the atmosphere at a particular place (changes frequently) |
| Climate | Average weather conditions of a place over a long period (~35 years) |
| Insolation | Incoming solar radiation; the Earth's primary energy source |
| Temperature | Degree of hotness or coldness measured by a thermometer |
| Lapse rate | Temperature decreases ~6.5°C per 1000 m increase in altitude |
| Atmospheric pressure | Weight of air above a given area; measured by a barometer |
| Humidity | Amount of water vapour in the air; measured by a hygrometer |
| Absolute humidity | Mass of water vapour per unit volume of air (grams per cubic metre) |
| Relative humidity | Ratio of actual water vapour to the maximum the air can hold (percentage) |
| Isolines | Imaginary lines joining places with equal weather values |
| Isotherms | Lines joining places with equal temperature |
| Isobars | Lines joining places with equal atmospheric pressure |
| Isohyets | Lines joining places with equal rainfall |
| Wind | Horizontal movement of air; types: planetary, seasonal, local |
| Meteorology | Scientific study of weather |
| Climatology | Scientific study of climate |
I. Choose the Correct Answer (MCQs)
1. Earth's atmosphere contains about percentage of nitrogen and oxygen.
- a) 78% and 21% b) 22% and 1% c) 21% and 0.97% d) 10% and 20%
The atmosphere has approximately 78% nitrogen and 21% oxygen.
2. _______ is generally defined as the average conditions of the weather of a place or a region.
- a) earth b) atmosphere c) climate d) sun
Climate is the long-term average of weather conditions over approximately 35 years.
3. The earth receives energy from
- a) current b) electro magnetic radiation c) waves d) heat
The Earth receives heat energy from the Sun through insolation.
4. Which represents places with equal amount of rainfall?
- a) isotherm b) isohel c) isobar d) isohyets
Isohyets are imaginary lines connecting places receiving equal rainfall.
5. _______ is used to measure humidity.
- a) anemometer b) barometer c) hygrometer d) thermometer
A hygrometer measures humidity; an aneroid barometer measures air pressure.
6. The word "Klimo" is derived from which language?
- a) Greek b) Latin c) Arab d) English
"Klimo" is a Greek word meaning "inclination" — the basis for the word "climate."
7. Horizontal movement of air is called
- a) Storm b) Cyclone c) Mist d) Wind
Wind is defined as the horizontal movement of air.
8. Temperature decrease per 1000 meters of height is
- a) 5°C b) 6.5°C c) 7°C d) 8.5°C
This is known as the lapse rate — temperature decreases ~6.5°C per 1000 m.
9. The difference between maximum and minimum temperatures of a day is
- a) Diurnal range b) Heat conduction c) Heat radiation d) Heat elevation
10. Which zone is called a Tropical Zone?
- a) Torrid zone b) Temperate zone c) Frigid zone d) Polar zone
11. Isobar means
- a) Equal sunshine b) Equal atmospheric pressure c) Equal temperature d) Equal rainfall
12. Equal amount of rainfall is called
- a) Isotherm b) Isohel c) Isohyet d) Isollobar
II. Fill in the Blanks
1. Weather refers to the condition of atmosphere for a short period of time. 2. The scientific study of weather is called Meteorology. 3. The highest temperature ever recorded on the earth is 56.7°C in USA. 4. Humidity is a ratio between the actual amount of water vapour and the maximum amount the air can hold. 5. Wind direction and wind speed are measured by anemometer and wind vane respectively. 6. Isotherms are imaginary lines which connect the same temperatures of different places. 7. Heat energy from solar radiation is received by the earth through three mechanisms. 8. Natural vegetation and soil are major factors affecting distribution of temperature. 9. Distribution of temperature is shown by means of Isotherms. 10. The word "Klimo" means Inclination. 11. Climate is the average atmospheric conditions usually for 35 years. 12. Scientific study of climate is called Climatology. 13. Amount of carbon dioxide in the atmosphere is 0.03%. 14. The scientific study of weather is called Meteorology. 15. The highest temperature ever recorded on Earth is 56.7°C in USA.
III. Match the Following
Textbook Match:
| No. | Column A | Answer |
|---|---|---|
| 1 | Climate | d) Long Term Changes |
| 2 | Isonif | c) Equal Snowfall |
| 3 | Hygrometer | e) Humidity |
| 4 | Radar | a) Locating and Tracking Storms |
| 5 | Low Pressure | b) Cyclone |
Additional Match:
| No. | Column A | Answer |
|---|---|---|
| 1 | Aneroid | e) Air pressure |
| 2 | Beaufort | c) Wind speed |
| 3 | Wind rose | b) Diagram |
| 4 | Fahrenheit | a) Temperature |
| 5 | Hydrometer | d) Humidity |
Third Match:
| No. | Column A | Answer |
|---|---|---|
| 1 | Isotherm | d) Equal temperature |
| 2 | Isobar | a) Equal pressure |
| 3 | Isohyet | b) Equal rainfall |
| 4 | Isohel | c) Equal sunshine |
| 5 | Isonif | e) Equal snowfall |
IV. True or False
V. Short Answer Questions
1. Define 'weather'. Weather refers to the day-to-day conditions of the atmosphere at any place, including sunshine, temperature, cloud cover, wind, fog, air pressure, humidity, and precipitation. It changes frequently and is studied under Meteorology.
2. What is insolation? Incoming solar radiation is called insolation. It is the primary source of energy for the Earth, received in the form of heat. The Earth's surface absorbs this solar energy and then radiates it back into the atmosphere, which is why the atmosphere is heated more from below than from above.
3. What is meant by atmospheric pressure? The weight of air above a given area on the Earth's surface is called atmospheric pressure or air pressure. It is measured by a barometer. Atmospheric pressure decreases with increasing altitude because there is less air above. Low pressure areas are associated with cyclones and cloudy weather, while high pressure areas are associated with clear skies.
4. Short note on "Planetary winds." Planetary winds blow almost in the same direction throughout the year, which is why they are also called permanent winds. They include trade winds (blow from subtropical high-pressure belts towards the equatorial low-pressure belts), westerlies (blow from subtropical belts to sub-polar low-pressure belts), and polar easterlies (blow from polar high-pressure belts to sub-polar low-pressure belts).
5. What are "Isolines"? Isolines are imaginary lines on maps that join places having equal values of weather elements. Examples include isotherms (equal temperature), isobars (equal pressure), isohyets (equal rainfall), isohels (equal sunshine), and isonifs (equal snowfall). They help meteorologists and geographers analyse spatial patterns of weather and climate.
6. What are the controlling factors of weather and climate? Major factors include the angle of the sun's rays, length of daytime, altitude, distribution of land and water bodies, location and direction of mountain ranges, air pressure, winds, and ocean currents. These factors interact to determine the weather and climate patterns of any given region.
VI. Distinguish the Following
Weather vs. Climate
| Feature | Weather | Climate |
|---|---|---|
| Definition | Day-to-day atmospheric conditions | Average weather conditions over a long period |
| Duration | Short-term (daily) | Long-term (about 35 years) |
| Changes | Changes frequently | Relatively stable |
| Example | Today it is sunny and 30°C | Chennai has a tropical wet and dry climate |
Absolute Humidity vs. Relative Humidity
| Feature | Absolute Humidity | Relative Humidity |
|---|---|---|
| Definition | Mass/weight of water vapour per unit volume of air | Ratio of actual water vapour to the maximum the air can hold |
| Unit | Grams per cubic metre | Expressed as percentage |
| Temperature | Varies with temperature | Preferred measure for weather forecasting |
Permanent Winds vs. Seasonal Winds
| Feature | Permanent (Planetary) Winds | Seasonal (Monsoon) Winds |
|---|---|---|
| Direction | Blow in the same direction all year | Change direction with seasons |
| Examples | Trade winds, Westerlies, Polar easterlies | Summer and winter monsoons |
| Other name | Planetary winds | Monsoon winds |
VII. Give Reasons
1. Weather and climate vary across different regions. Factors such as the angle of the sun's rays, length of daytime, altitude, distribution of land and water, location and direction of mountain ranges, air pressure, winds, and ocean currents affect weather and climate differently across regions.
2. Temperature decreases with increase in altitude. This is due to the lapse rate — temperature decreases approximately 6.5°C for every 1000 metres of altitude increase in the troposphere.
3. Mountain climbers carry oxygen cylinders while ascending peaks. At high altitudes, atmospheric pressure and available oxygen decrease significantly. Climbers use bottled oxygen to avoid decompression sickness and ensure breathing at elevations where oxygen is insufficient.
VIII. Detailed Answer Questions
Common Mistakes
1. ❌ Confusing weather and climate: Weather is short-term; climate is the average over ~35 years. ✅ Weather = today; Climate = long-term average. 2. ❌ Mixing up isotherms, isobars, and isohyets: Isotherms = temperature, isobars = pressure, isohyets = rainfall. ✅ Iso- = equal; then remember: therm = heat/temp, bar = pressure, hyet = rain. 3. ❌ Confusing Meteorology and Climatology: Meteorology is the study of weather; Climatology is the study of climate. ✅ Meteorology = weather (daily); Climatology = climate (long-term). 4. ❌ Wrong lapse rate: Temperature decreases 6.5°C per 1000 m, not 8°C. ✅ Remember: 6.5°C per 1000 m is the standard lapse rate. 5. ❌ Confusing absolute and relative humidity: Absolute is mass per volume; relative is a percentage ratio. ✅ Absolute = grams/m³; Relative = percentage. 6. ❌ Confusing permanent and seasonal winds: Permanent winds blow in the same direction year-round; monsoon winds change direction seasonally. ✅ Permanent = same direction; Monsoon = seasonal change. 7. ❌ Mixing up measuring instruments: Hygrometer = humidity, Barometer = pressure, Anemometer = wind speed. ✅ Hygro- = moisture/humidity; Baro- = pressure; Anemo- = wind.
Exam Checklist
- [ ] Can define and distinguish weather vs. climate
- [ ] Know the composition of the atmosphere (78% N₂, 21% O₂)
- [ ] Understand insolation and lapse rate (6.5°C/1000 m)
- [ ] Can list and explain all types of isolines (isotherm, isobar, isohyet, isohel, isonif)
- [ ] Can name instruments for measuring weather elements (thermometer, rain gauge, barometer, hygrometer, anemometer, wind vane)
- [ ] Can distinguish absolute vs. relative humidity, permanent vs. seasonal winds
- [ ] Know the three temperature scales (Celsius, Fahrenheit, Kelvin) and key temperature concepts (diurnal range, annual range, mean daily temperature)
- [ ] Remember that climate is based on ~35 years of data
- [ ] Understand the three types of wind and their characteristics (planetary, seasonal, local)
- [ ] Can explain why temperature decreases with altitude (lapse rate: 6.5°C per 1000 m)
- [ ] Know the composition of the atmosphere (78% N₂, 21% O₂, 0.03% CO₂)
- [ ] Can define and give examples of all isoline types
- [ ] Know the difference between dew, frost, fog, mist, and clouds as forms of condensation
Internal Links
- [Class 8 Social Science Guide](/class/8/social)
- [Weather and Climate — Chapter Guide](/class/8/social/weather-and-climate)
- [Rocks and Soils — Exercise Solutions](/class/8/social/solutions/rocks-and-soils-exercise-solutions)
- [Hydrologic Cycle — Exercise Solutions](/class/8/social/solutions/hydrologic-cycle-exercise-solutions)