This is maybe a more subtle task from a pure photographic viewpoint, but as an engineer you can always justify stuff like this by your curiosity. When playing around with the other air gun experiments, I started to think about the forensic engineers who do ballistic testing in water tanks. It is amazing how effective water is in taking the motion energy out of a bullet even at point blank and it makes it obvious that such a thing as sending a torpedo at high speed under water is not trivial...
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