Boyle's law is used to explain the inverse relationship between the pressure and volume of a container of gas held at a constant temperature. It was first discovered by Richard Towneley and Henry Power in the 17th century and was later confirmed and published by Robert Boyle a few years later.
Essentially, it states that when the pressure of a container filled with gas is increased, the overall volume of the container decreases (as demonstrated by this helpful visual animation).
Boyle's law can be mathematically stated as PV=k where P is the measurement of Pressure; V Volume and k a constant.
As long as the temperature and mass remain constant, the pressure and volume will also remain constant when multiplied together.
Real World Uses
Some of the most common uses for Boyle's law include:
- The human respiratory system - The expansion and contraction of the lungs serves as a good model;
- Canned carbonated drinks - Notice that when you open the can, the gas released balances out the internal volume;
- Spray cans - When shaken, the pressure inside of an aerosol can increase and when the top is pressed, this allows the pressurised gas escape (or 'expand' into a less pressurised environment, i.e. outside the can).
- Syringes - When the end is blocked and the plunger is pushed, the pressure inside of the syringe increases. The reduction in volume can be easily observed with this simple Boyle's law experiment.
Show Your Students How It Works
While a very basic experiment can be carried out by using a syringe where the student blocks the end and pulls/pushes the plunger to change the internal pressure; higher quality equipment will show the pressure/volume relationship much more clearly, making it easier for your students to learn.