The experimental gas law, more commonly known as “Charles Law,” explains the relationship between the volume of a given mass of gas and temperature. Also known as the “Law of Volume,” this law states that volume and temperature are directly proportional to each other.
Charles Law describes the expansion of gases when they are heated. Keeping it simple, we can say that as the temperature of any particular gas increases, the molecules in that gas exhibit increased movement. As soon as the movement of the molecule increases, there is an increased number of collisions. What happens is that the molecules begin to hit the walls of the container more frequently, and, that too, with an increased amount of force. If the wall of the container is flexible, say, a balloon, the pressure will remain constant; thereby, allowing the volume to increase. However, if the container is inflexible, the more frequent collisions will result in increased pressure.
In this article, we will talk about the real-life examples of Charles Law.
1. Helium Balloon
If you have had the chance to go out on a chilly day, you might have noticed that the balloon crumbles. However, if you take the balloon to a warm room, it regains its shape. Why does this happen? This happens because the temperature on a cold day is low, and, so, the volume decreases. Now, in accordance with the Charles Law, as soon as you enter a warm room, the temperature increases; with an increase in temperature, the volume also increases. Therefore, the balloon goes back to its original shape.
Charles Law finds its way into our kitchens as well. In case you have ever tried your hand at baking, you might be familiar with the substance most commonly used in cooking, i.e., the yeast. Yeast is often used in baking to make the bakery products fluffy. Yeast is responsible for releasing carbon dioxide bubbles. These carbon dioxide bubbles expand further with high temperature. The expansion of the carbon dioxide bubbles with an increase in temperature works as a leavening agent and cause the bakery products to become fluffy.
3. Hot Air Balloon
You might have wondered about the working of the hot air balloon. Charles Law describes that temperature and volume are directly proportional to each other. When a gas is heated, it expands. As the expansion of the gas takes place, it becomes less dense and the balloon is lifted in the air. The warm is less dense than the cold air, which means that it is lighter than the cold air. Also, the warm air has less mass per unit volume.
4. Turkey Timer
The working of the Pop-Up Turkey Timer (Thermometer) is also based on Charles law. Let’s see how! If you remember what the Charles law states, you might be familiar with the fact that gases expand when heated. The same principle applies to the Pop-Up Turkey Timer. The thermometer (or timer) is placed inside the turkey. As the temperature increases and the turkey cooks, the gas inside the thermometer also expands. As soon as the timer pops, it indicates that the turkey has been cooked.
5. Deodorant Spray Bottle
If you get a chance to read the instructions on a bottle of deodorant, you might have read the warning signs indicating the bottle to be kept away from the sunlight and high temperature. Ever wondered why? The answer lies in Charles Law. Under high temperatures, the air molecules inside the bottle will expand which can lead to the bursting of the deodorant bottle.
6. Ping Pong Ball
In case you play Ping Pong, chances are that you might have frequently come across a dented Ping Pong ball. How have you troubleshot such situation? You might have let your Ping Pong ball float on warm water for some time. Have you ever wondered why you do so? When you let your ball float on hot water, the temperature of the air inside the ball also increases; which, in turn, leads to an increase in the volume of the gas. Therefore, the shape of the ball is restored.
In cold weather, you might have regularly kept a check on the pressure of the tyres of your car. Driving increases the temperature of the tyres, and, therefore, the air inside the tyre warms and expands. When you measure the pressure of the tyres at the time when you have just driven the car, it will be high. However, in cold weather, the pressure of the tyres will be low. So, it is recommended that you should always measure the pressure of the tyres.
Most of you might have observed that a basketball when left outside on a cold winter night shrinks in size. As the temperature decreases, so do the volume of the gas inside the basketball. This forms the example that at constant pressure, a decrease in pressure will lead to a decrease in volume. However, the basketball gains its volume back when the environment is changed, i.e., you bring it in a warm room.
9. Pool Float
The pool floats forms yet another real-life example of Charles Law. You might have observed that after you inflate a pool float and push it into the pool, it seems a bit under-inflated. This is not because of any leak in the float. However, this happens because the temperature of the water in the pool is low, which reduces the volume of the air inside.
10. Automotive Engine
The power strokes of spark-ignition and compression-ignition also work in accordance with Charles Law. In spark ignition, gases from the very process of combustion are exposed to high temperature. Increase in temperature will lead to an increase in the volume of the gases. As this process continues, the force against the cylinder and piston head is increased, which causes rotation of the crankshaft. In diesel engines involving the process of compression ignition, the air is compressed under high temperature. This heated air combines with diesel fuel which is injected into the cylinder. The aforesaid process is responsible for the ignition of the diesel fuel.