Samuel Chiltern answered
Balloons are highly elastic, but they can only take a certain amount of pressure before they pop. If the pressure inside the balloon increases too much, then it will explode.
I'll explain how sunlight causes air to expand and to pop balloons in the rest of this answer.
The Effects of Heat on a Substance
When we measure the temperature of a substance, we are taking a reading of the average amount of kinetic energy exhibited by the molecules in that substance. In other words, we are establishing how quickly those molecules are moving.
In solids, molecules are fixed in place, so we are only measuring their vibrations when we take a temperature reading. In gases, however, molecules are freely moving about. This means that, when we measure the temperature of a gas, we are measuring the speed at which the molecules are moving around.
As molecules move about in air, they collide with other molecules. These collisions are what creates force, or what we would more commonly call pressure.
The Effects of the Sun on Balloons
When balloons are left in the sun, the heat from the sun's rays causes the air inside the balloon to heat up and expand, as the pressure increases. This expanding air causes the balloon's surface to expand as well.
If the air is heated enough, then the balloon will reach a point where it is no longer able to stretch to accommodate the expanding gas, and this will cause it to pop.
Remember the following simple rule: When the temperature of a gas increases, so does its volume.
I'll explain how sunlight causes air to expand and to pop balloons in the rest of this answer.
The Effects of Heat on a Substance
When we measure the temperature of a substance, we are taking a reading of the average amount of kinetic energy exhibited by the molecules in that substance. In other words, we are establishing how quickly those molecules are moving.
In solids, molecules are fixed in place, so we are only measuring their vibrations when we take a temperature reading. In gases, however, molecules are freely moving about. This means that, when we measure the temperature of a gas, we are measuring the speed at which the molecules are moving around.
As molecules move about in air, they collide with other molecules. These collisions are what creates force, or what we would more commonly call pressure.
The Effects of the Sun on Balloons
When balloons are left in the sun, the heat from the sun's rays causes the air inside the balloon to heat up and expand, as the pressure increases. This expanding air causes the balloon's surface to expand as well.
If the air is heated enough, then the balloon will reach a point where it is no longer able to stretch to accommodate the expanding gas, and this will cause it to pop.
Remember the following simple rule: When the temperature of a gas increases, so does its volume.
