Boyle’s law explains the relationship between the pressure and volume of a perfect gas. It states that the volume of a perfect gas is inversely proportional to the absolute pressure, provided temperature and the amount of gas remains constant. The particles of a gas are loosely packed in nature; therefore, they are free to move in their surroundings. When a container is filled with a perfect gas, its molecules tend to hit the boundary of the container. If the volume is decreased, the particles of gas hit the container much more frequently. Thereby, increasing the pressure. Similarly, on increasing the volume, the pressure is reduced. It is named after chemist and physicist Robert Boyle. He observed that when a compression force is applied to the gas present in a container, it acts as a spring and resists the compression force. This is the reason why the original law was published by him in the year 1662 with the title ‘the spring of the air.’
Examples of Boyle’s Law
During respiration, our lungs make use of Boyle’s law. While inhaling, the lungs are filled with air; therefore, they expand. The volume increases hence, the pressure level goes down. Similarly, when the lungs are evacuated of air, they shrink; therefore, the volume reduces and the pressure increases. The change in pressure and volume is momentary and periodic in nature.
2. Inflating Tyres
Flat tyres lack proper shape and strength, which makes it difficult for a vehicle to move properly. When air is pressed into flat tyres with the help of an air pump, the air molecules get tightly packed. The more be air molecules present in the tyre, the more will be the pressure exerted on the walls of the tyre. Hence, inflating flat tyres is yet another example of Boyle’s law in real life.
3. Soda bottle
A soda bottle filled with a mixture of carbon-di-oxide and the drink is one of the best examples to demonstrate Boyle’s law. When the soda can or bottle is sealed, it is difficult to compress. This is because the air molecules present inside the container are tightly packed and do not have space to move. When the can or the bottle is opened, some of the air molecules escape. Thereby, making space for the movement of air molecules and allowing the bottle to get compressed. Here, the change in pressure as per the change in volume can be clearly observed.
4. Working of a Syringe
A syringe is a medical equipment that is used to insert or withdraw fluids. It consists of a cylinder to contain the fluid and a plunger to vary the pressure. When the plunger is pushed down, the volume of the fluid reduces. Thereby, increasing the pressure. Similarly, on pulling up the plunger, the volume is increased and the pressure is reduced. Hence, the working of a syringe depends on Boyle’s law.
5. Spray Paint
Spray paints work on the basis of Boyle’s law. A significant amount of pressure is exerted by the paint molecules on the body of the can in which it is contained. When the top of the can is pressed, the volume inside the can gets reduced and the paint is thrown out with great pressure. Since the pressure has an inverse relationship with the volume, Boyle’s law can be observed in action.
Space does not consist of air or atmosphere. It has zero pressure as it is made up of a vacuum. As per Boyle’s law, when a pressurized gas enters a vacuum region, it will expand infinitely. This is the reason why astronauts wear specially designed spacesuits. In case the spacesuit of the astronaut gets ruptured, the blood and the body fluids start to boil and the astronaut gets seriously injured.
7. Scuba Diving
One thing to keep in mind when a person goes underwater diving is that he must balance the volume and pressure relationship to avoid getting sick or hurt. When he/she enters or approaches the depth of the water body, he/she experiences high pressure. The high pressure increases the solubility of gases in the human blood. When he/she tends to ascend or move upwards, the pressure begins to reduce and the gases present in the blood begin to expand. Hence, the diver must ascend at a slow rate to avoid any sort of injury. The relation between pressure and volume indicates Boyle’s law.
8. Cartesian Diver Experiment
The cartesian diver experiment is one of the most popular science experiment among kids. In this experiment or activity, a plastic bottle is thoroughly filled with water or any other fluid. An ear dropper filled with water is put inside the water bottle, the water is filled till the brim, and the cap of the bottle is fastened. When the bottle is squeezed the ear dropper goes down and on releasing the bottle the dropper goes up. Thereby, effectively demonstrating the action of Boyle’s law.