A Joule is a unit of energy.
Yesterday on the bike I was aiming to do half a metric century on the indoor bike. That then moved to “well, I’m close enough to 40 miles,” which in turn became “wow, I’m almost at 1000 kilo-Joules.”
I was on the bike for two hours and twenty minutes pedaling away at 120W.
I was proud for a moment — then I started to look around.
A megajoule is the amount of energy in a one-ton vehicle going at 100 miles per hour. It really puts things in perspective. My car, which weighs in very close to two tons, goes from zero to 100 in around 20 or so seconds (maybe quicker… dunno.) In that span of time 2 MJ of energy was added to the car — so let’s say 1 MJ took half that.
Suddenly, I feel puny. I know it’s not a level playing field, but what I took nearly two and a half hours, my car can do in ten seconds.
It’s also about the energy in about two pounds of TNT. Of course that would happen a lot quicker. That’s about half a stick of dynamite.
I think it puts things in perspective.