I've found a fish/luggage type of scale - one with a handle on top and a hook on the bottom - to be handy for larger rockets. I use it to weigh each section of the rocket individually.
Oh ... and I prefer a mechanical one (though it may not be as accurate). Whenever I needed it, the battery was always dead in the electronic one.
-- Roger
I fill the bathtub halfway with water and mark the level of the water on the side of the tub. Then I push the rocket under the water, making sure to get all of the rocket under but not any of my hands or fingers, and mark the new level. Then I calculate the volume of the difference. From there I can convert to weight knowing how much that water will weight.
You can use one of those fish scales to weigh the water. Just dip the hook into the water and lift the scale. Go slowly and be careful to keep the water from slipping off the hook before you get a good reading.
(BTW ... you're measuring the volume of the rocket, not its weight.)
-- Roger
I'm measuring volume first, and converting that to weight. The last sentence I mentioned that "From there I can convert to weight knowing how much that water will weight."
But your rocket is not made entirely of water. Consider the case of weighing a balloon in two ways. First use your method with the balloon empty and limp. Then repeat with it blown up and tied off. You will get two weights, neither of them correct.
Of course you and jadebox may be trolling for a laugh, too. (See what I did there?)
N
Good point. So instead of converting the volume of water to weight using density of water, I should first find out the density of rockets and use that. To find the conversion factor for water to rocket density I'll need to start with a large wooden badger, then I'll put....
I fill the bathtub halfway with water and mark the level of the water on the side of the tub. Then I push the rocket under the water, making sure to get all of the rocket under but not any of my hands or fingers, and mark the new level. Then I calculate the volume of the difference. From there I can convert to weight knowing how much that water will weight.
Fool proof and highly accurate.
I like the bathroom scale for yourself, then self plus rocket, and subtract method. I use it for bicycles all the time.
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Sadly this would not work for me in all cases. At 250 lbs with a 65 lb rocket and I've pegged the scale :(.
OH MY GOD!! People here can't understand sarcasm I guess. I was trying to be funny, but failed miserably. Not sure if it was me or the audience, but I'll accept responsibility.
OH MY GOD!! People here can't understand sarcasm I guess. I was trying to be funny, but failed miserably. Not sure if it was me or the audience, but I'll accept responsibility.
Here's some non-sarcastic explanations of my previous posts:
1) Putting a cardboard rocket under water will destroy the rocket, so that's a horrible way to attempt to measure anything about it anyway. I knew this when posting my first reply to this thread thinking this fact alone would clue builders in that this was a non-serious method to how to weigh a rocket.
2) I stated "foolproof and highly accurate" because I knew when posting it that it was neither of those. And to be clear, I mean that it was not a foolproof way to measure weight, nor a highly accurate way (as pointed out a few times already).
3) Bathtubs rarely have sides that are exactly vertical, so it would be seriously difficult to calculate volume of the change in water level. Another hit at the "highly accurate" claim I made.
4) You can't really slice off a top layer of water. Nobody actually tried to tell me that this wouldn't work - yet. But I thought I'd clear it up for those that are figuring out the best way to phrase their reply.
5) The large wooden badger was only a reference to a scene in a Monty Python movie, and not actually an item used to determine the density of rockets.
6) There would be no single density of rockets, as they're made of several different materials used in different quantities.
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