CBSE Important Questions for Class 6 Science A Journey through States of Water - 2025-26

1. What are the three states of water?
Water exists in three states: solid, liquid, and gas. The solid state is ice, where water molecules are closely packed and do not move freely. In the liquid state, water has a definite volume but takes the shape of its container, allowing molecules to flow. In the gas state, known as water vapour, water molecules are far apart and move freely, filling the available space.

2. How does water change from solid to liquid?
Water changes from solid to liquid through the process of melting. When ice is heated, the temperature rises, causing the molecules to gain energy. As they move faster, they begin to break apart from their fixed positions, resulting in the ice melting into liquid water.

3. What happens to water when it evaporates?
When water evaporates, it changes from a liquid to a gas, called water vapour. This process occurs when the water is heated, giving the molecules enough energy to escape from the surface of the liquid into the air. Evaporation is a key part of the water cycle, contributing to the formation of clouds.

4. What is condensation, and how does it occur?
Condensation is the process where water vapour cools down and changes back into liquid water. This typically happens when warm, moist air rises and cools. As the air cools, it can no longer hold all the water vapour, leading to the formation of water droplets, which can create clouds or dew.

5. Explain the water cycle.
The water cycle is the continuous movement of water through different states and locations on Earth. It includes processes such as evaporation (liquid to gas), condensation (gas to liquid), precipitation (rain, snow), and collection (water accumulating in rivers, lakes, and oceans). This cycle ensures that water is recycled and available for all living things.

6. How does temperature affect the state of water?
Temperature plays a crucial role in determining the state of water. As temperature increases, ice melts into liquid water, and liquid water can evaporate into gas. Conversely, cooling water can turn it into ice through freezing. Understanding this relationship is important for studying the behaviour of water.

7. What is thermal expansion?
Thermal expansion is the tendency of materials to change their size or volume when heated. When water is heated, it expands and takes up more space. This principle is important in understanding how substances behave when their temperature changes and is applicable in various fields, such as engineering and meteorology.

8. What are some uses of water in different states?
Water in its different states has various uses. Ice (solid) is used for cooling drinks and preserving food. Liquid water is essential for drinking, cooking, and sanitation. Water vapour (gas) is used in steam engines and in the process of humidifying air in buildings.

9. Why is the water cycle important?
The water cycle is important because it ensures the availability of fresh water for all living organisms. It helps regulate climate and weather patterns, supports plant growth, and replenishes groundwater. Understanding the water cycle is crucial for environmental conservation and management.

10. How does the process of freezing occur?
Freezing is the process where liquid water turns into solid ice. When water is cooled, the temperature drops and the molecules lose energy. As the molecules slow down, they come closer together and arrange themselves into a fixed structure, forming ice.

11. What role does evaporation play in cooling?
Evaporation plays a significant role in cooling because when water evaporates, it absorbs heat from the surrounding environment. This heat loss cools the surface from which the water evaporates. This is why sweating helps cool the body; as sweat evaporates, it takes heat away from the skin.

12. How can we demonstrate the water cycle in a simple experiment?
You can demonstrate the water cycle with a simple experiment using a clear container, some water, and a lid. Place water in the container, cover it with the lid and place it in sunlight. After some time, you will see condensation forming on the lid and droplets falling back into the container, simulating precipitation.

13. What is the significance of studying the states of water in Class 6?
Studying the states of water is significant because it lays the foundation for understanding various scientific concepts, such as changes in matter, the water cycle, and weather patterns. This knowledge is essential for further studies in science and helps explain natural phenomena.

14. How do humans impact the water cycle?
Human activities, such as deforestation, urbanization, and pollution, can disrupt the natural water cycle. For example, cutting down trees reduces transpiration, while urban areas increase runoff and decrease groundwater recharge. Understanding these impacts helps in promoting sustainable practices to protect water resources.

15. What are some common misconceptions about water states?
Common misconceptions include the idea that water only exists in liquid form or that ice is just cold water. In reality, water can exist as solid, liquid, or gas, depending on temperature and pressure. Understanding these states helps clarify how water behaves in different conditions.

16. What is the difference between evaporation and boiling?
Evaporation occurs at any temperature and only at the surface of a liquid, while boiling happens at a specific temperature (the boiling point) throughout the liquid. In boiling, bubbles form and rise to the surface, while in evaporation, no bubbles are formed. Understanding this difference is important for grasping how water changes states.

17. How does humidity affect the process of evaporation?
Humidity refers to the amount of water vapour in the air. When humidity is high, the air is already saturated with moisture, making evaporation slower. Conversely, low humidity allows water to evaporate more quickly. This relationship is important for understanding weather patterns and drying processes.

18. What experiments can be done to show how temperature affects the states of water?
One simple experiment is to take a cup of ice and place it in a warm room. Observe how the ice melts into water as the temperature increases. Another experiment involves heating water in a pot and watching it turn into steam, demonstrating the change from liquid to gas. These experiments help illustrate the effect of temperature on water's states.

19. What is the process of transpiration, and how is it related to the water cycle?
Transpiration is the process by which plants release water vapour into the air through their leaves. This process contributes to the water cycle by adding moisture to the atmosphere, which can lead to condensation and precipitation. Understanding transpiration helps explain the connection between plants and the water cycle.

20. How can the concept of states of water be applied in daily life?
The concept of states of water is applied in various everyday situations, such as cooking (boiling water), weather (rain and snow), and cooling (ice in drinks). Recognizing how water changes states helps us understand many practical applications, from food preparation to climate awareness.

Extra Questions for Class 6 Science Chapter 8 A Journey through States of Water

Very Short Answer Type Questions

Q1: What are the three states of water?
A1: The three states of water are solid (ice), liquid (water), and gas (water vapour).

Q2: Name the process by which water changes from liquid to gas.
A2: The process by which water changes from liquid to gas is called evaporation.

Q3: What is condensation?
A3: Condensation is the process by which water vapour (gas) cools and changes back into liquid water, forming water droplets.

Short Answer Type Questions

Q4: Explain why water puddles disappear after rain.
A4: Water puddles disappear after rain due to the process of evaporation. When the sun heats the water, it turns into water vapour and rises into the air, causing the puddles to dry up.

Q5: Describe the process that occurs when water from a wet cloth dries in the sun.
A5: When water from a wet cloth dries in the sun, the heat causes the water to evaporate. The liquid water turns into water vapour and escapes into the air, leaving the cloth dry.

Q6: How does water vapour condense to form water droplets on a cold surface?
A6: When water vapour comes into contact with a cold surface, it cools down and changes from gas to liquid. This process is called condensation, and it forms water droplets on the cold surface, such as the outer surface of a cold glass.

Q7: What happens to water when it is heated to its boiling point?
A7: When water is heated to its boiling point (100°C), it undergoes boiling, where it changes from liquid to gas (water vapour). The water starts to bubble and evaporate at the boiling point.

To excel in CBSE Class 6 Science, focusing on key chapters is essential, and Chapter 8: "A Journey through the States of Water" is one of the most important. Vedantu has created a set of important questions, short answers, and test paper-style exercises for this chapter.

Practising these will strengthen your understanding and help you prepare effectively for exams. For additional revision, extra questions are also included. Download the Class 6 Science Important Questions FREE PDF to study anytime and boost your exam readiness.

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