Question With Answer Class 6 Science Chapter 8

Chapter 8 of Class 6 Science, A Journey through States of Water, explains the basic features that make an organism live. Through simple questions and answers, students can easily understand this chapter.

Let Us Enhance Our Learning

---

1. In how many states does water exist? Explain.

Answer:
Water exists in three states:

1. Solid – Ice
   
2. Liquid – Water
   
3. Gas – Water vapour (steam)
   

Water changes its state when temperature changes.

---

2. What is melting point? What is the melting point of water?

Answer:
The temperature at which a solid changes into a liquid is called its melting point.
The melting point of ice (water) is 0°C.

---

3. What is boiling point? What is the boiling point of water?

Answer:
The temperature at which a liquid changes into gas is called its boiling point.
The boiling point of water is 100°C.

---

4. What is evaporation?

Answer:
The process by which water slowly changes into water vapour at room temperature is called evaporation.
Example: Drying of wet clothes.

---

5. What is condensation?

Answer:
The process by which water vapour changes into liquid water on cooling is called condensation.
Example: Water droplets on the outside of a cold glass.

---

6. What is freezing?

Answer:
The process by which water changes into ice on cooling is called freezing.
Water freezes at 0°C.

---

7. What is sublimation?

Answer:
The process in which a solid directly changes into gas without becoming liquid is called sublimation.
Example: Camphor and naphthalene balls.

---

8. Why does ice float on water?

Answer:
Ice floats on water because it is less dense than water.

---

9. Why do wet clothes dry faster on a hot and windy day?

Answer:
Wet clothes dry faster because:

• High temperature increases evaporation.
  
• Wind carries away water vapour quickly.
  

---

10. What is water cycle?

Answer:
The continuous process of evaporation, condensation, and rainfall is called the water cycle.

Steps:

1. Sun heats water → Evaporation
   
2. Vapour cools → Condensation
   
3. Clouds form → Rainfall