Post by Kenshou Ine on May 18, 2015 22:09:32 GMT -5
My posts are going to be educational, so you're going to learn things. Like science things, from a real engineer. So here, we will keep a running tab of what topics we cover and link to the posts they are in.
Post by Kenshou Ine on May 18, 2015 22:36:06 GMT -5
So first up is the ideal gas law. This is a pretty important bit of thermodynamics, because well a lot of stuff is built off of this one little equation.
PV = nRT
That is a pretty sexy equation if I do say so, it's so simple and yet has so many applications. Let's take a quick look and break this baby down.
P - Pressure
V - Volume
n - Number of moles
R - Gas Constant
T - Temperature
I bet like 90% of you can look at that and understand at least 3 of those 5. So we will be only explaining the number of moles and gas constant bits.
Moles? Furry friends underground or something else? Well a mole is actually a unit of measurement. 1 mol is equal to 6.022x1023 pieces. (Some may recognize this as Avogadro's number.) Typically we talk about a mol of an atom type, but it can also be for a compound. Such as 1 mol of H (Hydrogen) or 1 mol of H2O (Water). The point is that 1 mol will equal out to the mean molar mass. This means if you have 1 mol of Carbon, then that is equal to 12.01 grams of Carbon.
This means that our n is useful to us in telling us the amount that is involved in our Ideal Gas Law.
R, this is the gas constant. This comes from a combination of things but mostly it's related to Boltzman's constant. We could work this out, but I will assume most of you would get lost somewhere in the amount of equations we'd burn through and having to have it all explained. That's not a dig at how smart you guys are, but I mean it's complicated when you don't have the right background. Now the units for this are (P*V)/(n*T). Some might have realized that this balances out our equation in terms of units. The most typical expression of R is 8.314 J/(mol-K).
Now, what does the Ideal Gas Law tell us? Basically it represents the perfect world, where if you know all but 1 of those things you can figure the last one out.
Well Ine, how does this relate to me? What can I do with this?
Well you like American Football? You like Tom Brady? You want to see some science on deflategate?
Here's the cool thing about the Ideal Gas Law, assuming that your container doesn't allow any change in the amount of something in it (n) and the internal volume doesn't change (V) then you can do something pretty cool with an initial and final state of your system.
This is also known as the Guy Lussac's Law. Now what this says is that if we measure our football's pressure at the beginning of the game and record the temperature. That the pressure divided by the temperature must equal the pressure at the end of the game divided by the temperature at the end of the game. This means if they are not equal, someone let air out of the balls. That's the hard science.
Of course in the real world you have to account for some leakage from a non perfect seal, but the amount would have to be nearly negligible. That is how we know the Patriots are cheating pieces of shit and cost me $20.
Comment below, letting me know if this was too simple, complicated, just right, or whatever. Ask questions and I'll do my best to answer.
Most people need to know how to do prob/stat stuff. Do that one. It's easy enough to understand in a segment about this size, and it is hella useful in day to day life.