## For the Fourth

I was in my apartment for the 4th of July fireworks this year, but fortunately a local television station simulcasts the fireworks on T.V., so I can watch them from home.  It was a very elaborate show, and they actually have music to which the fireworks are synchronized.  I was very excited when I noticed that when the opened with “Heavy Action” (a.k.a. the MNF theme song) and the music from the T.V. was actually synchronized with the faint reports I was hearing from the actual fireworks!

How is this possible?  Well, ever since Superbowl XXXVIII live broadcasts almost have to have a delay.  So what sort of delay does the feed have to produce this happy coincidence?

As it turns out, according to Google Maps and its “Distance Measurement Tool”, I live about 2 miles from the fireworks ground zero.  The speed of sound in air is strictly a function of temperature (for an ideal gas); it was 66 F ($\approx$ 19 C) according to my external thermometer.  Per Wikipedia:

$c=331\tfrac{m}{s}\sqrt{1+\frac{T}{273.15 C}}=331\tfrac{m}{s}\sqrt{1+\frac{19}{273.15 C}}$
$c=342\frac{m}{s}$

So if 2 miles = 3.2 km = 3200 meters, then at 342 m/s, it would take the sound of each firework over 9 seconds to reach me.  This seems like a slightly excessive, but welcome television delay.  Thanks overbearing FCC!  Without you, I would have to actually monitor what my future kids watched on T.V., and I wouldn’t get treated to synchronized fireworks television/noise!

### 2 Responses to “For the Fourth”

1. Shaz says:

Favorite post so far!

Also, I’ve finally started reading your posts. You’ve officially made it to my RSS feed and the “Interesting Links” portion of my own page. That’s kind of a big deal.

• K-Mob says:

Is it your favorite because I alluded to Janet Jackson’s naked breast?

Be honest to me, the internet, and yourself.