HARD
6th CBSE
IMPORTANT
Earn 100

Why is a mercury thermometer used to measure temperature?

Important Questions on Changes Around Us

MEDIUM
6th CBSE
IMPORTANT
Head Start Science 6>Chapter 6 - Changes Around Us>EXERCISES>Q 4
Why can a tight metallic lid on a glass bottle be opened easily if immersed in hot water for some time?
MEDIUM
6th CBSE
IMPORTANT
Head Start Science 6>Chapter 6 - Changes Around Us>EXERCISES>Q 5
Why are gaps left between rails on a railway track?
EASY
6th CBSE
IMPORTANT
Head Start Science 6>Chapter 6 - Changes Around Us>EXERCISES>Q 6
What are reversible and irreversible changes? Give examples.
HARD
6th CBSE
IMPORTANT
Head Start Science 6>Chapter 6 - Changes Around Us>EXERCISES>Q 1
Justify the statement - physical changes can be reversible as well as irreversible.
MEDIUM
6th CBSE
IMPORTANT
Head Start Science 6>Chapter 6 - Changes Around Us>EXERCISES>Q 2
Justify the statement giving examples — heating brings about chemical changes in some substances whereas physical changes in others.
HARD
6th CBSE
IMPORTANT
Head Start Science 6>Chapter 6 - Changes Around Us>EXERCISES>Q 3
Addition of water to salt or sand is a physical change whereas to cement is a chemical change. Justify the statement.
HARD
6th CBSE
IMPORTANT
Head Start Science 6>Chapter 6 - Changes Around Us>EXERCISES>Q 4
Why does a glass tumbler containing hot water crack if we cool it by pouring cold water on it?
MEDIUM
6th CBSE
IMPORTANT
Head Start Science 6>Chapter 6 - Changes Around Us>EXERCISES>Q 5
Have you ever lighted a candle on festivals, birthdays or some other occasions? You must have observed the following when a candle is lighted: 
• Candle burns to produce carbon dioxide, water vapour and light. 
• The size of the candle decreases. 
• Some of the wax melts. 
Now classify the above changes as reversible or irreversible.