Inflating Balloon

QUESTION:Can a balloon inflate when heated

Equipment:

A Bowl
A Balloon
Ice cubes
Hot water
An empty soda bottle
Method:

1.Place an empty soda bottle in a bowl of ice-cubes.

2.After about 10 minutes when the bottle has become cold take the bottle out the bowl.

3. Place a deflated balloon over the neck of the bottle and leave it out.

4.After the bottle has returned to room temperature, place it in a bowl of hot water.

5.The balloon starts getting inflated once the bottle gets hot.
Observation:When the bottle was placed in the cold water the balloon did not inflate. But when we placed it in the hot water the balloon inflated.

Explanation
The balloon inflated when the bottle was placed in the hot water because the warm air expands.This caused an increase in pressure in the bottle which inflated the balloon.