Give two main sources of carbon.
The main sources of carbon are:
Give two examples of non-renewable resources.
Non-renewable exhaustible resources are those that once exhausted cannot be replenished. Fossil fuels, minerals are all examples of non-renewable resources.
Give two effects of soil erosion.
Two effects of soil erosion are:
Give role of atmosphere in climatic control.
The atmosphere keeps the average temperature of the earth fairly steady during the day as the atmosphere prevents the sudden increase in temperature during the daylight hours and at night atmosphere slows down the escape of heat into the outer space.
Explain what is smog. Give its effects.
Smog is a photochemical haze caused by the action of solar ultra violet radiation on atmosphere polluted with primary pollutants such as hydrocarbons and oxides of nitrogen from automobile exhaust. It reduces visibility and is highly suffocating and toxic to humans, animals and plants.
Explain the direction of air movement during the day and night in coastal areas.
In coastal areas, during daytime, there is a regular flow of cool air from the sea towards the land. At night, there is a reverse flow of air from land to sea. This happens because during the daytime, land gets heated faster than water.
Explain rain water harvesting.
Rainwater harvesting is a technique used to capture and store rain water by making special water harvesting structures so that there is an increase in the recharge of underground water resources.
Explain phenomenon of acid rain.
When fossil fuels such as coal and petroleum products are burnt, they produce oxides of nitrogen and sulphur. On dissolving in rain these oxides form nitric acid and sulphuric acid respectively. This causes acid rain. These acids wash down into the soil and make it highly acidic, thus, affecting the growth of plants and ultimately the forest growth. It also affects the surface of buildings by eroding the stone and brick works.
Explain carbon monoxide poisoning.
Carbon monoxide is a colourless, odourles gas produced by burning of wood, fuels etc. The replacement of oxygen with carbon monoxide in red blood cells in our body leads to carbon monoxide poisoning. Carbon monoxide poisoning causes tissue damage and may even lead to death.
Describe the major components of air pollution.
The major components of air pollution are soot, fly ash, dust particles, smoke and some gases like sulphur dioxide, carbon monoxide, nitrogen oxide, ammonia etc.
Demonstrate the formation of convective currents.
When the solar radiations fall on the earth, some are absorbed and majority of these are reflected back or re-radiated by the land and water bodies. These reflected or re-radiated solar radiations heat the atmosphere from below. As a result convection currents are set up in the air.
Define water pollution.
Contamination of water bodies with undesirable substances like fertilizers, pesticides or poisonous substances, thus degrading the water quality and making it unfit for drinking and other purposes is defined as water pollution.
Define the weather.
The short term changes in the properties of the troposphere forms the weather. The weather changes take place everyday. It tells us about the temperature, rain, cloud and sunshine of an area.
Define renewable resources?
Renewable exhaustible resources are those resources that may get exhausted by excessive use but can be re-obtained in nature. Eg- Forests; they might disappear one day if deforestation continues but planting seeds can regenerate them.