Physics is a killer

I blame crappy science education.

Tampa teen dies in fireworks accident
A 16-year-old boy holding a mortar firing tube and trying to launch it when it exploded late Thursday night has died, Tampa police said.

Point one: Mortars work like guns. When you fire a mortar placed on the ground, the launch charge detonates. Newton’s Second Law of motion goes into effect. The force of the charge operates on the shell and the tube. The tube can’t move because it’s pushed against the ground. The remaining force acts on the shell, expelling it from the tube into the sky.

When you stupidly hold the tube in your hand, the charge’s force still works on tube and shell, but now the tube can be pushed down. Recoil. Less force acts on the shell. As a result, the shell the shell doesn’t go up into the sky. It detonates in your face.

Please consider that those beautiful mortar displays involve material rapidly distributed over — even with consumer-grade shells — as much as hundreds of feet. That’s a significant explosion. Pretty, hundreds of feet up in the sky.

Lethal, when it happens in your face.

It ain’t like launching a bottle rocket with the bottle (or pipe, or whatever) held in your hand. It’s a rocket, not a gun. Newtons’ Second Law is acting on the rocket exhaust and the rocket body. Not the launch tube so much. You can get away with that if the rocket operates correctly.

Not mortars. There’s only so much propelling force to go around, and if it isn’t distributed to the shell, the shell will hang around… your face.

Students, if your school has something resembling a real science class, pay attention.

Parents, if the school’s “science” class consists of “the water cycle” year after year*, without touching on basic physics, find a real school.


* Sadly, a real world example.

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2 thoughts on “Physics is a killer

  1. Clare July 6, 2018 / 1:10 pm

    Very sad.
    Regarding the water cycle repetition, I think you will remember that such was offered my son over and over in school. In helping a couple neighborhood kids with their homework in the last few years, I saw it again: water cycle taught year after year in science class!

    Like

    • Bear July 6, 2018 / 4:58 pm

      That’s just who I was thinking of.

      Like

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