To reduce global warming, it is expected that people will not do one of the following:
- Increase the burning of fossil fuels
- Turning off electrical gadgets when not in use
- Plant more trees
- Switch to eco-friendly cars
Answer
Increase the burning of fossil fuels
Reason — To reduce global warming we need to decrease the emission of GHGs by reducing the burning of fossil fuels, so increasing the burning of fossil fuels is the one thing people are expected not to do. Turning off electrical gadgets when not in use, planting more trees and switching to eco-friendly cars are all measures that help reduce global warming.
The ozone molecules are destroyed in the ozone layer:
- By the intense sunlight
- By the chlorine atoms released from CFC
- By the CO₂, NO₂, and SO₂ gases released by burning of fossil fuels
- By volcanic activities
Answer
By the chlorine atoms released from CFC
Reason — CFCs contain chlorine. UV radiation causes a chlorine atom to break away from a CFC molecule. The free chlorine atom then attacks an ozone molecule and removes one of its oxygen atoms, thereby destroying the ozone molecule. Therefore, chlorine released from CFCs is the direct agent responsible for ozone destruction in this process.
Mention two points to differentiate weather from climate.
Answer
| Weather | Climate |
|---|---|
| Weather refers to the conditions of the atmosphere of a particular place over a short period of time. | Climate is the average condition of the atmosphere calculated over a long period of 35 years or more. |
| It is highly dynamic and may change very quickly. | It is more stable and permanent in nature. |
How are weather conditions recorded?
Answer
Weather conditions are recorded by observing and measuring the different elements of weather — such as temperature, humidity, precipitation, wind direction, velocity and cloud cover — with the help of weather instruments at meteorological stations. Artificial satellites also provide images and data used for weather forecasting.
Name the factors that affect the temperature of a place.
Answer
The temperature of a place may vary due to the following factors:
- Difference in the latitudinal position
- Altitude
- Distance from the sea
- Ocean currents
- Wind
- Vegetation cover
What causes varying pressure at different places?
Answer
Atmospheric pressure varies at different places due to altitude, temperature, moisture content and the rotation of the Earth:
- Pressure decreases with altitude as the air becomes thinner or less dense.
- Warm air expands and rises, creating low pressure, while colder, denser air sinks and creates high pressure.
- Wet air exerts less pressure than dry air.
- The rotation of the Earth deflects winds and influences the formation of high-pressure and low-pressure zones.
Why is climate more steady than weather?
Answer
Climate is based on the average weather conditions of a place over a long period of 35 years or more. Short-term changes in weather are therefore averaged out. Hence, climate is more stable and permanent than weather.
Give example — an intrusive igneous rock
Answer
Granite
Give example — Sedimentary rocks
Answer
Sandstone, shale, limestone and rock salt
Give example — Rocks that are used to produce energy
Answer
Coal
Give example — Metamorphic rocks
Answer
Marble, slate, graphite, schist and diamond
Give example — A precious stone which is a metamorphic rock
Answer
Diamond