Previously, we have looked at the property of heat-transfer in terms of smoking paraphernalia design. It is important to remember, while smoking, that the laws of physics are at work! Here, we are going to discuss another quintessential property of physics—pressure.
Now everybody knows what pressure is, we can feel it. It is in our nose when we have a cold, we can feel it whenever we are pressing down on something; pressure is completely inescapable in our daily lives.
But what is it, in a physical sense, and why is it so imperative to the smoking process?
Pressure is defined as a force per unit area, such as pounds per square inch (PSI). In order to calculate the pressure something feels, you take the force applied, then divide by the area of the afflicted area.
For example, if you are smoking out of a bong or a pipe, we have to apply a negative force via inhaling. If you inhale with the same intensity on a pipe and a bong, the pipe will deliver the smoke much faster! This is because the affected area in a pipe is smaller than the effected area in a bong. This is why one must suck harder out of larger pieces to bring the smoke to the mouthpiece.
Well, this is intuitive, is it not? Yet very interesting to think about the mechanics when we go to the microscopic scale!
Our entire universe follows the rules of gradients. In other words, something will always move from an area of high intensity to low intensity, such as a drop of food coloring (high intensity) diffusing throughout a liquid with a low intensity of color. This principal can be applied to just about anything including the ever famous “gravity bong.”
Gravity bongs, for those who may not know, are a type of bong constructed from a bowl, a large bottle with the bottom removed and a bucket full of water.
First, you submerge the bottle in the bucket full of water, such that only the top is out of the water. Put the bowl on the top, add some herb and light it. While it is lit you raise the bottle out of the water and the bottle fills with smoke.
There are a few principals at work here: gravity, surface tension and pressure!
The gravity is holding the water down, the surface tension is creating a seal between the water and as the bottle is raised, a vacuum is created in the bottle. This vacuum can be thought of as negative pressure (low intensity) forcing the air from the outside to pass through the burning weed (high intensity) and fill the bong with smoke. Once the bottle is out of the water, the seal is gone and is no longer pulling smoke down.
You see, science is constantly permeating through every aspect of our lives, so let’s figure out how to harness it for our own gain. One such way would be to take advantage of Bernoulli’s principle.
Bernoulli’s principle essentially states that a fast moving fluid (water, air, etc.) will have a lower pressure than the same fluid at a slower speed. How is this useful?
After one is done smoking there is ash in the bowl, you could blow into the bowl, but then you’d get ash all over your face. But if you blow over the top of the bowl, then you create a pressure difference.
Now remember “stuff” moves from high to low, so if you decrease the pressure of the air over the bowl, by blowing over it (speeding up the air), then the air inside the bowl (high pressure) will carry the debris into the air above the bowl (low pressure). Once you lift the ash out, your blowing will carry it away. Boom, practical science for the everyday stoner!
Hopefully you will take what you have learned here, and let your self sit back in awe the next time you light up. Remember to always appreciate the world around you, even the hidden world of science!