# Examples of Charles's law in real life

### Examples of Charles's Law in Reality:

Charles's law states that the volume of a given mass of a gas is directly proportional to its kelvin temperature, provided the pressure remains constant. This law was formulated by French Physicist, Jacques Charles in 1780.

Various instances of Charles's law are seen around us. They include the following:

• #### Restoring dented table tennis ball

Children who had dented their table tennis (or ping-pong) balls will be familiar with Charles's law through an attempt of fixing it.

One way they go about this process is by placing the dented surface of the table tennis ball on warm water for some time. As the ball floats, the increased temperature within that surface on the table tennis ball causes an increase in the volume of gas present inside the ball. This is what Charles's law entails; and it causes the table tennis ball to expand in this instance, until its dented surface is restored to normalcy.

• #### Use of yeast in baking

Charles's law is applicable whenever yeast is utilized for baking purposes. Recall that yeasts serve the purpose of making our bakery products swell and fluffy. It is able to do this because it releases carbon (IV) oxide (CO2) when heated at high temperature.

As the temperature increases, the volume occupied by the gas bubbles of carbon (IV) oxide also increases through its spreading around the baked product, making it swell in the process.

The baking of bread is a typical example of this process, and it works in accordance with Charles's law.

• #### Pop-up turkey timer

The pop-up turkey timer is a type of thermometer whose mechanism of action is based on Charles's law. Within this timer is a gas that expands based on the available quantity of heat (temperature).

Recall that with Charles's law, when temperature increases, volume also increases.

Before the heating or roasting process, the thermometer (timer) is inserted inside the turkey. As it gets heated up, the turkey's temperature increases, bringing about an expansion (increase in volume) of the gas within the thermometer. A volume will eventually be reached, and it results into a pop sound by the thermometer. This pop-up by the thermometer indicates that the turkey had been cooked.

• #### Bursting of balloons

Have you ever wondered why a balloon could burst without been touched? Well, the simple answer is Charles's law which states that an increase in temperature results into an increased volume at constant pressure.

When a balloon is filled with air (or helium gas), then tied and exposed to a sunny condition (high temperature), the volume occupied by the gas within the balloon increases due to the high environmental temperature. This causes the balloon to expand and eventually burst due to the lightness of its material, its elastic nature, the increased volume of its gas and an increased temperature.

However, the volume of gas occupied within the balloon decreases on cold days (due to low temperature). As a result, helium balloons tend to shrink on cold days.

• #### Hot air balloon

Jaques Charles himself utilized his law when he had a hydrogen balloon flight. In fact he was said to be a lover of hot air balloon.

At a basic level, hot air balloon comprises of a burner, an envelop that stores hot air and a gondola (or basket) that carry passengers. In order to fly, the hot air inside the envelop is first heated immediately after the fuel source had been ignited.

This increased temperature causes the air to expand, thus increasing its occupied volume, while also making it lighter (since it has less mass per unit volume), in contrast to the denser cooler air present outside the envelop (that is, the atmosphere). The hot air balloon goes higher up the sky through this process.

• #### Pool float

When filled with air, a pool float enables one to float on water. However, it is quite common for a pool float to become under-inflated when placed on a pool. This happens as a result of Charles's law.

The cause of an under-inflated pool foalt is a result of the pool's low temperature. As a result, the volume of air within it is reduced, resulting into its slightly shrinked size.

If the pool float were to be placed on warm water, its occupied gas volume will increase, making it inflated again.

It is a common observation that an inflated basketball shrinks in size when left under a cold environment. This is true because a decrease in temperature results into a corresponding decrease in volume according to Charles's law. Therefore, the volume of air inside the basketball shrinks on cold day.

As you may have guessed, the volume of the basketball will be regained when placed in an environment with higher temperature since the volume occupied by the air within it increases.

• #### Explosion of aerosols

Aerosols refers to products like insecticides, perfumes, deodorants, spray paints and so on. They usually have two compartments within their container. These are the primary liquid product, for instance, the perfume, paint or an insecticide chemical, and a highly pressurized sealed gas which had become solution.

If an aerosol is exposed to a very high temperature, it may explode. This is true because when heated, the pressurized gas expands and increases in volume. Since the gas cannot escape from its locked nozzle, it eventually explodes. In fact, this is the reason behind the warning signs on its container, indicating that it should be stored in a cool environment, and kept away from the sunlight and high temperature.

• #### Human lungs

With regards to the human body system, the air capacity of the human lungs decreases during cold conditions. Simply put, the volume of air received in the lungs is somewhat reduced due to its decreased environmental temperature.  This implies less energy for daily activities, and may impact adversely on the performance of athletes, especially sprinters.

On the contrary, the air capacity of the lungs increases on a sunny day (higher temperature), allowing more air into it. This mechanism is explained through an internal bodily regulation called homeostasis.

Other examples of Charles's law in real life are observed in the following instances:

• Opening a soda drink from a can or bottle

• Inflating and deflating tyres

• Storage of gas

• Car engines

• Boiling of water in a covered pot