Class 6 Science Question Answers - Changes Around Us

Short Answer Questions

Q1: What is an example of a fast change?
Ans: Burning of paper is an example of a fast change.

Q2: Give an example of a slow change.
Ans: The aging of the human body is an example of a slow change.

Q3: Explain one desirable change.
Ans: Bees changing nectar into honey is a desirable change as it benefits us.

Q4: What is the main difference between physical and chemical changes?
Ans: In physical changes, the substance's properties stay the same, while in chemical changes, new substances with different properties are formed.

Q5: How can you change matter from its liquid state to its solid state?
Ans: Matter can be changed from a liquid state to a solid state by reducing the temperature, such as freezing water to form ice.

Long Answer Questions

Q1: Explain the concept of reversible changes with examples.
Ans: Reversible changes are changes that can be turned back to their original form. For example, freezing water into ice is a reversible change, as you can melt the ice back into water. Another example is knitting a cap using wool, which can be unraveled and the wool reused.

Q2: Describe the differences between desirable and undesirable changes, and provide examples of each.
Ans: Desirable changes are beneficial, like the growth of plants from seeds and honey production by bees. Undesirable changes, on the other hand, are harmful, such as rusting and the rotting of fruits. Desirable changes have positive impacts, while undesirable changes can lead to negative consequences.

Q3: Explain how energy is involved in various changes. Provide examples.
Ans: Energy is involved in changes as it is either used or released. For example, the heat and light energy produced when wood burns is an example of energy being released during a change. The morning sunlight provides energy for flowers to bloom, showing how energy is used in initiating changes.

Q4: Discuss the formation of salt solution as a physical change and give examples of other physical changes.
Ans: The formation of a salt solution is a physical change because both salt and water retain their properties and can be separated. Other examples of physical changes include the melting of ice, mixing sand and water, cutting wood, and breaking glass.

Q5: Provide examples of common irreversible changes and explain why they cannot be reversed.
Ans: Irreversible changes involve the formation of new substances. For example, burning sugar results in the formation of carbon, and rusting of iron creates iron oxide. These changes cannot be reversed because they involve chemical reactions that alter the original substances permanently.