a) Water is a vital element that is necessary for the survival of all living organisms on our planet. It plays a crucial role in sustaining life and supporting various biological processes.
b) Freshwater, also known as potable water, is the type of water that is safe for consumption. It undergoes processes such as purification and treatment to remove impurities and make it suitable for drinking.
c) When we consider Earth's surface, approximately 71% is covered by water. However, only a small portion of that water, about 3%, is fresh water. The remaining 97% consists of saltwater found in oceans and seas.
a) There are different sources of water that contribute to the availability of this vital resource.
b) These various sources of water collectively contribute to the water cycle, which is the continuous movement and circulation of water on Earth.
a) The water cycle, also known as the hydrological cycle, describes the continuous movement of water between different water bodies such as oceans, rivers, ponds, lakes, and the atmosphere.
b) It is a vital natural process that sustains the availability of water on Earth. The water cycle can be summarized as follows:
a) The water cycle is a continuous process that ensures the distribution, purification, and recycling of Earth's water resources.
b) It is essential for maintaining the balance of ecosystems, providing water for human consumption, supporting agriculture, and driving weather patterns.
c) Understanding the water cycle helps us appreciate the interconnectedness of water and its significance for life on Earth.
a) A flood occurs when there is an overflow of water in rivers, lakes, and ponds due to excessive rainfall.
b) This excess water surpasses the capacity of these water bodies, leading to the flooding of surrounding areas.
Floods can have various effects, including:
Floods are natural disasters that can have devastating impacts on communities and ecosystems. Effective flood management, including early warning systems, proper land-use planning, and infrastructure development, can help minimise the adverse effects of floods and protect vulnerable areas.
Drought is a prolonged period of time in which a region experiences significantly low rainfall, resulting in a scarcity of water resources.
Droughts can have severe consequences for both the environment and human populations.
a) Here are some key points about drought and its effects:
b) Efforts to reduce the effects of drought include water conservation measures, such as efficient irrigation techniques, water recycling, and implementing drought-resistant agricultural practices.
a) Rainwater harvesting is the practice of collecting and storing rainwater for future use.
b) It involves capturing rainwater from rooftops, land surfaces, or other catchment areas and directing it into storage tanks, cisterns, or underground reservoirs.
c) This collected rainwater can then be used for various purposes.
Here are some key points about rainwater harvesting and its benefits:
a) Air is an essential component of our environment, surrounding us everywhere. It is a mixture of various gases and tiny dust particles.
b) Understanding the properties and composition of air is important for various scientific and environmental studies.
c) Additionally, air plays a crucial role in supporting life, as it provides oxygen for respiration and serves as a medium for sound transmission.
Here are some key points about air:
a) Air is composed of various constituents, including nitrogen, oxygen, carbon dioxide, water vapour, dust, and smoke.
b) Understanding the constituents of air is important for studying air quality, environmental pollution, and the interactions between living organisms and their surroundings.
c) It highlights the significance of maintaining a balance of gases, such as oxygen and carbon dioxide, for the sustenance of life on Earth.
Here are some key points about these constituents:
a) Understanding the different layers of the atmosphere helps us comprehend the distribution of temperature, pressure, and various phenomena that occur within each layer.
a) Air plays a crucial role in supporting life and various ecological processes. Here are some important aspects highlighting the significance of air:
b) The importance of air extends beyond these points, as it also influences weather patterns, climate regulation, and the overall health of ecosystems.
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1. How does the water cycle prevent the Earth from running out of fresh water?
The water cycle continuously recycles water through evaporation, condensation, and precipitation. This ensures that fresh water is always replenished, despite being used for drinking, agriculture, and industry.
2. Why is air essential for combustion (burning)?
Air contains oxygen, which is a necessary component for combustion. When chemicals burn, they react with oxygen from the atmosphere.
3. How does air pollution affect the quality of air and living organisms?
Air pollution introduces harmful substances like carbon monoxide, nitrogen oxides, and particulates into the atmosphere, which can harm respiratory health, damage ecosystems, and contribute to global warming.
4. How do water and air interact to form weather patterns?
Water and air interact through processes like evaporation, condensation, and wind movement. Warm air rises, carrying water vapour, which cools and condenses into clouds. This interaction causes weather patterns like rain, storms, and wind.
5. How do human activities influence the layers of the atmosphere, particularly the ozone layer?
Human activities, such as the release of chlorofluorocarbons (CFCs), damage the ozone layer by breaking down ozone molecules. This leads to the thinning of the ozone layer, allowing more UV radiation to reach the Earth's surface.
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