Chapter 8. A Journey through States of Water-Extra Questions Examination Based Science Curiosity Class 6 In English

Chapter 8. A Journey through States of Water

The following important questions are prepared according to the latest CBSE pattern and the NCERT Curiosity textbook. These questions cover conceptual understanding, competency-based learning, and examination-oriented practice.

Important Questions with Answers

Practice these questions regularly to strengthen your understanding of the chapter and improve your performance in school examinations.

1 Mark Questions

Answer each question in one sentence.

Question 1. Name the three states in which water exists.

Answer: Water exists in solid (ice), liquid (water), and gaseous (water vapour) states.

Question 2. What is evaporation?

Answer: Evaporation is the process of changing liquid water into water vapour.

Question 3. What is condensation?

Answer: Condensation is the process in which water vapour changes into liquid water.

Question 4. What is melting?

Answer: Melting is the process of changing a solid into a liquid on heating.

Question 5. What is freezing?

Answer: Freezing is the process of changing a liquid into a solid on cooling.

Question 6. What is humidity?

Answer: Humidity is the amount of water vapour present in the air.

Question 7. Give one example of evaporation in daily life.

Answer: Drying of wet clothes is an example of evaporation.

Question 8. Why do water droplets appear on the outer surface of a cold glass?

Answer: Water vapour in the air condenses on the cold surface of the glass.

Question 9. Name one factor that increases evaporation.

Answer: High temperature increases evaporation.

Question 10. What is the water cycle?

Answer: The continuous movement of water between the Earth's surface and the atmosphere is called the water cycle.

2 Marks Questions

Answer each question in about 30–40 words.

Question 1. Differentiate between evaporation and condensation.

Answer:

Question 2. Why do clothes dry faster on a windy day?

Answer: Wind continuously removes water vapour from the surface of clothes, increasing the rate of evaporation. Therefore, clothes dry faster on windy days.

Question 3. Write any two examples of condensation.

Answer:

• Water droplets on a cold glass.
• Dew drops on grass in the morning.

Question 4. Mention any two uses of evaporation in daily life.

Answer:

• Drying washed clothes.
• Cooling the body through sweating.

Question 5. Why is water called a unique substance?

Answer: Water is called a unique substance because it naturally exists in all three states—solid, liquid, and gas—under normal conditions on Earth.

3 Marks Questions

Answer each question in about 50–70 words.

Question 1. Explain the three states of water.

Answer:

Water exists in three physical states. Ice is the solid state with a fixed shape and volume. Liquid water has a fixed volume but takes the shape of its container. Water vapour is the gaseous state and has neither a fixed shape nor a fixed volume. These states change into one another through heating and cooling.

Question 2. Explain the cooling effect of evaporation with suitable examples.

Answer:

During evaporation, water absorbs heat from its surroundings before changing into vapour. This removes heat and produces cooling. Sweating cools our body, water remains cool in an earthen pot, and hand sanitiser gives a cooling sensation because of evaporation.

Question 3. Describe the factors affecting evaporation.

Answer:

Evaporation becomes faster when the temperature is high, the exposed surface area is large, and air movement is greater. High humidity slows down evaporation because the air already contains a large amount of water vapour.

Question 4. Explain how clouds are formed.

Answer:

Water evaporates from rivers, lakes, and oceans. The water vapour rises into the atmosphere where the air is cooler. It condenses around tiny dust particles to form small water droplets. Millions of these droplets together form clouds.

Question 5. Explain the stages of the water cycle.

Answer:

The water cycle consists of evaporation, condensation, precipitation, and collection. Water evaporates, forms clouds through condensation, falls as rain or snow, and finally collects in rivers, lakes, oceans, and underground sources before repeating the cycle.

Long Answer Questions

Answer each question in detail.

Question 1. Explain the changes of state of water with the help of a flow diagram.

Answer:

Water changes its state when heat is supplied or removed. Heating converts ice into water and water into water vapour. Cooling changes water vapour into water and water into ice.

These are physical changes because no new substance is formed during the process.

Question 2. Explain the process of evaporation and discuss the factors affecting it.

Answer:

Evaporation is the process by which liquid water changes into water vapour. It occurs continuously, even at room temperature. The rate of evaporation increases with higher temperature, greater surface area, and stronger air movement. It decreases when the humidity of the surrounding air is high. Evaporation is responsible for drying clothes, cooling the body through sweating, and many other everyday phenomena.

Question 3. Explain the cooling effect of evaporation with suitable examples.

Answer:

When water evaporates, it absorbs heat from the surrounding objects. This loss of heat produces a cooling effect. Sweating cools the human body because sweat evaporates from the skin. Water stored in earthen pots remains cool due to slow evaporation through tiny pores. Hand sanitisers and perfumes also produce a cooling sensation because they evaporate quickly.

Question 4. Describe the formation of clouds and rainfall.

Answer:

The Sun heats water present in rivers, lakes, ponds, and oceans. Water evaporates and rises into the atmosphere as water vapour. At higher altitudes, the air becomes cooler, causing condensation around tiny dust particles. This forms clouds. As water droplets combine and become heavier, they fall to the Earth as rain. In colder regions, precipitation may occur as snow or hail.

Question 5. Explain the importance of the water cycle.

Answer:

The water cycle continuously recycles water on Earth. It supplies fresh water to rivers, lakes, plants, animals, and human beings. It also maintains the balance of nature, supports agriculture, replenishes groundwater, and helps regulate weather and climate. Without the water cycle, life on Earth would not be possible.