Question 1: Define the term 'evaporation' in the context of the water cycle.

Answer: Evaporation is the process by which water is converted from liquid to vapour and rises into the atmosphere.

Question 2: Explain how condensation contributes to cloud formation.

Answer: Condensation occurs when water vapour cools and changes back into liquid droplets, forming clouds.

Question 3: Describe the process of precipitation in the water cycle.

Answer: Precipitation is when water droplets in clouds become heavy enough to fall to the ground as rain, snow, sleet, or hail.

Question 1: If a lake has an average evaporation rate of 5 mm per day over an area of 10 km², calculate the total volume of water evaporated in one day. (1 mm = 1 litre per square metre)

Answer: 50,000,000 litres

Question 2: A cloud contains approximately 1,000,000 water droplets, each with a volume of 1 cubic millimetre. Calculate the total volume of water in the cloud in litres. (1 litre = 1,000,000 cubic millimetres)

Answer: 1 litre

Question 1: Outline a simple experiment to demonstrate evaporation and list the safety precautions that should be observed.

Answer: A suitable experiment involves placing a shallow dish of water in a sunny spot and covering it with plastic wrap. Observe the formation of water droplets on the inside of the wrap over time. Precautions include avoiding direct contact with hot surfaces, ensuring the area is well-ventilated, and handling any hot equipment carefully.

Question 1: In a particular region, during a dry season, the average daily rainfall recorded was 2 mm, and the average evaporation rate was 6 mm. Discuss the impact of this imbalance on local water resources and ecosystems.

Answer: The higher evaporation rate compared to rainfall leads to a net loss of water, causing drought conditions, reduced water availability for plants and animals, and potential negative impacts on ecosystems.

Question 1: Explain the importance of the water cycle for maintaining life on Earth, including how it supports ecosystems and human activities. Include specific processes and their significance in your answer. (6 marks)

Answer: The water cycle is essential for maintaining life as it enables the continuous movement and distribution of water across different parts of the Earth. Processes like evaporation transfer water from surface bodies to the atmosphere, while condensation forms clouds, leading to precipitation that replenishes water sources. This cycle supports ecosystems by providing necessary water for plants and animals, maintaining habitat stability, and enabling nutrient transport. For humans, it supplies freshwater for drinking, agriculture, and industry. The cycle also helps regulate climate and weather patterns, making it vital for sustaining life on Earth.

Question 1: Describe how understanding the water cycle can help in designing effective water management systems in urban areas.

Answer: Understanding the water cycle helps urban planners design systems that maximise water collection, storage, and recycling, such as rainwater harvesting and drainage systems, to ensure sustainable water supply and reduce flooding.

Question 2: Discuss how climate change might affect the water cycle and the implications for agriculture and water security.

Answer: Climate change can alter the water cycle by increasing temperatures, leading to higher evaporation rates, changing rainfall patterns, and more frequent droughts or floods. These changes can reduce water availability for agriculture, threaten water security, and disrupt ecosystems. Adaptation strategies include improved water conservation, developing drought-resistant crops, and better management of water resources.