# i'm a maths nerd and proud

4

so I saw this post (x) and I was like, wait a second, Barry’s lighting that gas on fire by moving his fingers? How fast is Barry moving?

If you look closely, there’s a label that says that the gas is propane, which has a molar mass of 44.10 g/mol, a specific heat of 1.67 J/g*K, and autoignites at 743 K. So, Barry has to be moving, at the minimum, fast enough to reach 743 K.

So, let’s say he’s igniting 1 mole of propane (there’s really no way to measure the mass by watching) and that the room temperature is a standard 298 K. With Q=mcΔt, we have:

Q = (44.10 g)(1.67 J/g*K)(743 K - 298 K)

Q = 32772.915 J or 32772.915 kg*m^2*s^-2

Then, we have the total thermal energy from Barry’s two fingers moving! So, to find the velocity, I used 1/2mv^2=Q. For the mass of a human finger, I used 100 g since that was the first result from google. I use 1/2mv^2 twice, one for each finger’s movement:

½(0.1 kg)v^2 + ½(0.1 kg)v^2 = 32772.915 kg*m^2*s^-2

(0.1 kg)v^2 = 32772.915 kg*m^2*s^-2

v^2 = 327729.15 m^2*s^-2

v= 572.4763313885 m/s

Then, I converted the velocity to miles per hour:

572.4763313885 m/s * 60 s/min * 60 min/hour * 0.000621371 mile/m = 1280.5926858403 miles per hour

Barry snapped his fingers at, at the least, 1280 miles per hour or Mach 1.68. To put that into perspective, he had to run straight for 5.3 miles in season 1 to reach Mach 1.1 so he could supersonic punch Tony Woodward.

That’s one fast snap.