Q69. Make two paper cups by folding a sheet of paper. Pour about 50 mL of water in one of the cups. Heat both the cups separately with a candle. What do you observe?
a. What happens to the empty paper cup and why?
b. What happens to the paper cup with water and why?
c. Does water in this cup become hot?
Q70. How will you show that air is necessary for combustion?
Write an activity to show that oxygen is necessary for combustion.
How would you show that air is needed for combustion?
How will you show that air is essential for burning fuels?
What will happen if a burning candle is covered with a glass jar?
Write an experiment to show that air is essential for burning.
Q71. Explain the structure of candle flame with diagram.