Content

# Balloon theory

#### The weight of air

The air is composed of a quantity of gases whose weight depends on temperature and atmospheric pressure. Therefore, the weight is always determined from a standard temperature (atmosphere at zero point one degrees Celsius).

The air is comprised of nearly 80 percent nitrogen and about 20 percent oxygen. In an atmosphere at zero point one degree Celsius, a liter of air weighs approximately 1.3 grams while a liter of water weighs one kilo (1000 grams).

Imagine you have a huge elastic, cube-shaped balloon with exactly 1 cubic meter. The balloon interior contains exactly 1000 liters of air with a temperature identical to that of the air outside the balloon. The weight of these 1000 liters of air inside the balloon is 1300 grams.
The air is composed of a quantity of gases whose weight depends on temperature and atmospheric pressure. Therefore, the weight is always determined from a standard temperature (atmosphere at zero point one degrees Celsius).

The air is comprised of nearly 80 percent nitrogen and about 20 percent oxygen. In an atmosphere at zero point one degree Celsius, a liter of air weighs approximately 1.3 grams while a liter of water weighs one kilo (1000 grams).

Imagine you have a huge elastic, cube-shaped balloon with exactly 1 cubic meter. The balloon interior contains exactly 1000 liters of air with a temperature identical to that of the air outside the balloon. The weight of these 1000 liters of air inside the balloon is 1300 grams.
The air is composed of a quantity of gases whose weight depends on temperature and atmospheric pressure. Therefore, the weight is always determined from a standard temperature (atmosphere at zero point one degrees Celsius).

The air is comprised of nearly 80 percent nitrogen and about 20 percent oxygen. In an atmosphere at zero point one degree Celsius, a liter of air weighs approximately 1.3 grams while a liter of water weighs one kilo (1000 grams).

Imagine you have a huge elastic, cube-shaped balloon with exactly 1 cubic meter. The balloon interior contains exactly 1000 liters of air with a temperature identical to that of the air outside the balloon. The weight of these 1000 liters of air inside the balloon is 1300 grams.

#### Hot air expands

The gases existing in the air (nitrogen and oxygen) are made up of molecules. These molecules are in constant motion and the velocity at which they move depends on the temperature of the gas amount, among other factors.

The molecules move more rapidly when the temperature increases, knocking against each other and against all close objects. A molecule that collides with an object at a low speed exerts a small force on this object, but when a molecule collides with the same object at a higher speed it will also exert a greater force on the same object.

The molecules are in constant motion against the balloon walls. The faster the molecules move, the greater the force at which they collide against the the balloon walls and therefore the greater the force they exert on these walls. Since the balloon walls are elastic, this expands with the increasing air force.

Try it for yourself:
Fill a normal balloon with air and knot it tightly.
Now with a metric tape measure the balloon circumference and record the value.
You can even draw a line around the balloon with a pencil, so as to return to measure at the same place.

Then place the balloon in the sun. Under the influence of sunlight, the air will become warmer and the balloon will expand.
After a while, upon re-measuring the balloon, you will find that the balloon is higher than when it was cold. You may notice this phenomenon, observing the balloon during its heating.

It’s possible that the balloon will burst upon expanding!
The gases existing in the air (nitrogen and oxygen) are made up of molecules. These molecules are in constant motion and the velocity at which they move depends on the temperature of the gas amount, among other factors.

The molecules move more rapidly when the temperature increases, knocking against each other and against all close objects. A molecule that collides with an object at a low speed exerts a small force on this object, but when a molecule collides with the same object at a higher speed it will also exert a greater force on the same object.

The molecules are in constant motion against the balloon walls. The faster the molecules move, the greater the force at which they collide against the the balloon walls and therefore the greater the force they exert on these walls. Since the balloon walls are elastic, this expands with the increasing air force.

Try it for yourself:
Fill a normal balloon with air and knot it tightly.
Now with a metric tape measure the balloon circumference and record the value.
You can even draw a line around the balloon with a pencil, so as to return to measure at the same place.

Then place the balloon in the sun. Under the influence of sunlight, the air will become warmer and the balloon will expand.
After a while, upon re-measuring the balloon, you will find that the balloon is higher than when it was cold. You may notice this phenomenon, observing the balloon during its heating.

It’s possible that the balloon will burst upon expanding!
The gases existing in the air (nitrogen and oxygen) are made up of molecules. These molecules are in constant motion and the velocity at which they move depends on the temperature of the gas amount, among other factors.

The molecules move more rapidly when the temperature increases, knocking against each other and against all close objects. A molecule that collides with an object at a low speed exerts a small force on this object, but when a molecule collides with the same object at a higher speed it will also exert a greater force on the same object.

The molecules are in constant motion against the balloon walls. The faster the molecules move, the greater the force at which they collide against the the balloon walls and therefore the greater the force they exert on these walls. Since the balloon walls are elastic, this expands with the increasing air force.

Try it for yourself:
Fill a normal balloon with air and knot it tightly.
Now with a metric tape measure the balloon circumference and record the value.
You can even draw a line around the balloon with a pencil, so as to return to measure at the same place.

Then place the balloon in the sun. Under the influence of sunlight, the air will become warmer and the balloon will expand.
After a while, upon re-measuring the balloon, you will find that the balloon is higher than when it was cold. You may notice this phenomenon, observing the balloon during its heating.

It’s possible that the balloon will burst upon expanding!

#### Less air is synonymous with less weight

The balloon expands with the heating of air in its interior. Before heating, the balloon volume is 1000 liters, but after heating this value increases by 10%. Thus, the same amount of air increases its volume to 1100 liters. However, the weight of that amount of air continues to be 1300 grams.

You can also observe another phenomenon.

In the space that previously contained 1300 grams of air, there is now less weight because the expansion increased air volume by 10%.

Instead of 1300 grams in 1000 liters, 1300 grams in 1100 liters are now recorded. By calculating based on 1000 liters, we find that the weight decreased (1000/1100 =) 0.909 times, or reached (1.300 * 0.909 =) 1182 grams (approximately). Thus, the weight decreased by about 118 grams!
The balloon expands with the heating of air in its interior. Before heating, the balloon volume is 1000 liters, but after heating this value increases by 10%. Thus, the same amount of air increases its volume to 1100 liters. However, the weight of that amount of air continues to be 1300 grams.

You can also observe another phenomenon.

In the space that previously contained 1300 grams of air, there is now less weight because the expansion increased air volume by 10%.

Instead of 1300 grams in 1000 liters, 1300 grams in 1100 liters are now recorded. By calculating based on 1000 liters, we find that the weight decreased (1000/1100 =) 0.909 times, or reached (1.300 * 0.909 =) 1182 grams (approximately). Thus, the weight decreased by about 118 grams!
The balloon expands with the heating of air in its interior. Before heating, the balloon volume is 1000 liters, but after heating this value increases by 10%. Thus, the same amount of air increases its volume to 1100 liters. However, the weight of that amount of air continues to be 1300 grams.

You can also observe another phenomenon.

In the space that previously contained 1300 grams of air, there is now less weight because the expansion increased air volume by 10%.

Instead of 1300 grams in 1000 liters, 1300 grams in 1100 liters are now recorded. By calculating based on 1000 liters, we find that the weight decreased (1000/1100 =) 0.909 times, or reached (1.300 * 0.909 =) 1182 grams (approximately). Thus, the weight decreased by about 118 grams!

#### Heavy objects fall, but lighter objects float

The force of gravity attracts all objects.

The air inside the balloon weighs 1300 grams and is therefore pulled down towards the ground by gravity.  The air surrounding the balloon also suffers from gravity’s action.

As explained above, the heated air inside the balloon is lighter than the cold air surrounding it. Thus, the heated air is propelled upward relative to the cold air.

Now it’s a matter of comparison: if the force with which the heated air is driven upwards is greater than the force of gravity attracting the balloon downwards, then you can feel the submission of gravitational force to the hot air as this rises towards the sky.
The force of gravity attracts all objects.

The air inside the balloon weighs 1300 grams and is therefore pulled down towards the ground by gravity.  The air surrounding the balloon also suffers from gravity’s action.

As explained above, the heated air inside the balloon is lighter than the cold air surrounding it. Thus, the heated air is propelled upward relative to the cold air.

Now it’s a matter of comparison: if the force with which the heated air is driven upwards is greater than the force of gravity attracting the balloon downwards, then you can feel the submission of gravitational force to the hot air as this rises towards the sky.
The force of gravity attracts all objects.

The air inside the balloon weighs 1300 grams and is therefore pulled down towards the ground by gravity.  The air surrounding the balloon also suffers from gravity’s action.

As explained above, the heated air inside the balloon is lighter than the cold air surrounding it. Thus, the heated air is propelled upward relative to the cold air.

Now it’s a matter of comparison: if the force with which the heated air is driven upwards is greater than the force of gravity attracting the balloon downwards, then you can feel the submission of gravitational force to the hot air as this rises towards the sky.

#### Where does the impulsion force come from?

What makes the balloon rise when it is lighter than the surrounding air?

The explanation lies in Archimedes’ Principle. Archimedes was a wise man at the beginning of our era, who discovered the principle behind these phenomena. The impulsion force of each object is equal to the weight of matter (air in this case) that will be replaced by the same object. In other words, the air that was in place of the balloon weighed 1300 grams. The balloon with heated air has replaced this air. Thus, there is an impulsion force of 1300 grams following the cold air replaced by the balloon with hot air.

Archimedes’ Principle also explains why a football floats in water:
If we push a plastic ball with 5 liters of air under water, this will replace 5 liters of water.
5 liters of water weighs 5000 grams.

According to Archimedes’ Principle, this substitution results in an impulsion force of 5000 grams.

The ball and the air inside naturally have a set weight, particularly about 500 grams for the ball and 5 liters of air, 1.3 grams per liter, which amounts to 506.5 grams.
Since an impulsion force of 5000 grams is considerably greater than the weight of the ball, this will rise to the water surface.

What makes the balloon rise when it is lighter than the surrounding air?

The explanation lies in Archimedes’ Principle. Archimedes was a wise man at the beginning of our era, who discovered the principle behind these phenomena. The impulsion force of each object is equal to the weight of matter (air in this case) that will be replaced by the same object. In other words, the air that was in place of the balloon weighed 1300 grams. The balloon with heated air has replaced this air. Thus, there is an impulsion force of 1300 grams following the cold air replaced by the balloon with hot air.

Archimedes’ Principle also explains why a football floats in water:
If we push a plastic ball with 5 liters of air under water, this will replace 5 liters of water.
5 liters of water weighs 5000 grams.

According to Archimedes’ Principle, this substitution results in an impulsion force of 5000 grams.

The ball and the air inside naturally have a set weight, particularly about 500 grams for the ball and 5 liters of air, 1.3 grams per liter, which amounts to 506.5 grams.
Since an impulsion force of 5000 grams is considerably greater than the weight of the ball, this will rise to the water surface.

What makes the balloon rise when it is lighter than the surrounding air?

The explanation lies in Archimedes’ Principle. Archimedes was a wise man at the beginning of our era, who discovered the principle behind these phenomena. The impulsion force of each object is equal to the weight of matter (air in this case) that will be replaced by the same object. In other words, the air that was in place of the balloon weighed 1300 grams. The balloon with heated air has replaced this air. Thus, there is an impulsion force of 1300 grams following the cold air replaced by the balloon with hot air.

Archimedes’ Principle also explains why a football floats in water:
If we push a plastic ball with 5 liters of air under water, this will replace 5 liters of water.
5 liters of water weighs 5000 grams.

According to Archimedes’ Principle, this substitution results in an impulsion force of 5000 grams.

The ball and the air inside naturally have a set weight, particularly about 500 grams for the ball and 5 liters of air, 1.3 grams per liter, which amounts to 506.5 grams.
Since an impulsion force of 5000 grams is considerably greater than the weight of the ball, this will rise to the water surface.

#### The weight of the balloon itself

The balloon structure naturally has its own weight, however insignificant it may be.

This balloon weight should be added to the weight of air inside.

If the weight is below both the impulsion force caused by the replacement of the air, the balloon will then rise
The balloon structure naturally has its own weight, however insignificant it may be.

This balloon weight should be added to the weight of air inside.

If the weight is below both the impulsion force caused by the replacement of the air, the balloon will then rise
The balloon structure naturally has its own weight, however insignificant it may be.

This balloon weight should be added to the weight of air inside.

If the weight is below both the impulsion force caused by the replacement of the air, the balloon will then rise

back