by Cyrus Irani

Created on: September 23, 2008   Last Updated: November 10, 2010

Boyle's law states that if the temperature of a gas is kept constant, the pressure if the gas is inversely proportional to the volume. Which suggests that in an ideal situation where the temperature does not change, if either the pressure or volume is increased the other one will decrease by the same proportion.
Its formula is:

PV = K
Or
V = (K) 1/P
Or
V 1/P

Where
P = Pressure

V = Volume
K = Constant

A few very interesting examples regarding Boyle's Law in everyday life are discussed below:

1. Change of Pressure in a Syringe
A syringe is an everyday device used in a hospital to draw blood samples or give injections.
When the plunger of the syringe is pulled back the volume of the syringe container increases, decreasing the pressure inside since the same amount of gas is now spread over a greater volume. To balance this effect of low pressure, air or blood is sucked in through the needle, thus balancing the pressure inside and outside the container.

2. The popping of a Balloon
When we try to squeeze a balloon we are actually trying to reduce the volume of the gas inside, which increases the pressure. Since the balloon cannot withstand the added pressure it bursts.

3. Increase in size of bubbles as they rise to the surface
We've all seen movies showing scuba divers breathing under water and bubbles growing as they rise to the surface. This is a good example of Boyle's Law in nature. We know that the deeper we go in the sea, more the pressure. Therefore as the bubbles rise to the surface the pressure decreases and accordingly the volume increases.

4. Death of deep sea creatures due to change in pressure.
Another sea related example would be of deep sea creatures dying if they are brought to the surface of the sea.
Deep sea fish are accustomed to the high pressure of the deep sea. Their bodies are built to counter the external water pressure. When brought to the surface the pressure inside their body is greater than the pressure of the surrounding water hence the balance is disturbed and the membranes of their bladders and cells pop due to increase in volume.

5. Popping of ears at high altitude
We often feel a very uneasy pain in our ears while in a plane during ascending and descending. This is due to the imbalance of air pressure inside and outside the ear drums.
When the plane starts to rise it is going from an area of high pressure where your ears are accustomed to, to an area of low pressure. As the inside pressure of your ears increases with altitude compared to the surrounding, the air inside increases in volume straining your eardrums. Therefore it is necessary to swallow hard in order to clear passage for the opening tube located in your throat, allowing the excess pressure to escape.

For Examples of Charles Law

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