The ‘Gas Laws’ is an umbrella term for 4 principles that sought to explain the relationship of gases to volume, temperature and pressure.
They’re more than 200-years old so it may seem a curious topic for a technical article in 2017, but I often find it’s useful to revisit ‘First Principles’ as they are of such importance, and find application in fields as broad as gauges, munitions, diving and countless other areas.
The volume of a gas is proportional to the pressure
The pressure exerted on the walls of a vessel are proportional to the temperature
At a given temperature and volume, all gases contain the same number of molecules.
Each of these laws interact with each other; they don’t work in isolation. The General Gas law encompasses all of the above
|Pop-corn is another, far-safer example. The fleshy endosperm of the popcorn contains about 15% water. Placed in hot oil or butter, it softens and expands, eventually vaporising the water contained and as described by Messrs Boyle and Gay-Lussac, the expanding gas and steam puts huge pressure onto the walls of the kernel until it can no longer withstand the pressure and bursts into the tasty snack we know and love.
Both Charles law and Gay-Lussac are at play here.
The sad, left-over, un-popped corn kernels probably had a porous skin that allowed moisture to escape and the pressure was not able to build.
Hopefully you’re aware that Homershams supply quality pressure gauges. These pressure gauges contain a mechanism based on a Bourdon tube.
The sealed Bourdon tube is forced to obey the laws of nature and expands when gas pressure is applied. By attaching a pointer to the end of the tube we can create an accurate pressure measuring device, based again on the work of our old friend Boyle.
A bullet is propelled by the expanding gases from the burning powder/propellant, expanding rapidly to force the projectile out with enormous force and speed.
Incidentally if you’d like to learn more about our IANZ accreditation, have a look at Homershams scope of accreditation.