A Silly Question About Mass and Weight.
-
by
Kitharode
moderator
On the assumption that one day we'll be able to transport a boulder or three from Mars back to Earth, and assuming also that strict weight limits are imposed for rocket launching and the like, then what methods of measuring weight will be used by the astronauts who collect the boulders. The question, I think, also relates to the Apollo landings and moon rock collection.
Is it guesswork? A calibrated spring thingy? Fill that box and call it a day? Silly, but I just don't know.
Posted
-
by
angi60
in response to Kitharode's comment.
Knock, knock. Excuse me, sorry I'm late. I've been at another class, taught by your twin. Would you mind if I join this class?
That's an interesting question - I hadn't thought of that. And normal 'scales' would be affected by the different gravity!
Posted
-
by
Kitharode
moderator
Who's There! Oh "Hi" Angie60. Please do join in.
Exactly what I thought. Normal scales will tell us what it weighs on Mars, so do astronauts carry a conversion chart? But are the scales working differently because of weaker gravity, giving a 'false' reading? I'm embarrassed to say that I can't quite get my head around that.
It did cross my mind that maybe we could use a ruler to measure the rocks. If we knew an average density for the rocks in our landing area, then I think we could find its mass. If so, then we'd know how much it weighed on Mars. So could we say that a rock that was 'this big' would weigh 'this much' on Mars, which would then tell us how much they would weigh on Earth? I think so - and it'd also fit in with my 'box full' theory, hahaha!
It might be one way, but I don't know if that's what NASA would do. 😉
Posted
-
by
angi60
in response to Kitharode's comment.
Yes, same here - not my strong point! OK, this is some info from NASA:-
Apollo 11 collected 21kg rocks. I couldn't find any mention of weighing, but scales are listed in the equipment list for Apollo missions.
The largest rock on Apollo 15 weighed 9.6kg!
Mars Curiosity is using a SAM Instrument (Sample Analysis at Mars) which selects and processes samples (inc weighing).
The six Apollo missions brought back a total of 381.7 kg (2196 samples)!! Do you think we could carry that much from our trip to Mars?!Posted
-
by
Kitharode
moderator
Hey that's good stuff. Scales are listed, eh? So they're measuring/weighing something. Well done.
I'm guessing these are earth weights given by NASA, seems sensible enough. For efficiency I guess that some sort of unmanned 'cargo ship' might be an answer to your last question. If you find out what those Apollo scales were used for I'd love to know.
Nowt like a silly question to spark some good answers ... 😉
Posted
-
by
angi60
Yes, I'll see if I can find out more. Not a silly question at all! You're certainly exercising my brain, which had started to atrophy! I've just asked a question in the 'Objects' thread about an image I've just had.
Posted
-
by
Kitharode
moderator
Density x Volume = Mass. (Looked it up just to be sure - old age and all that)!
So we can use a ruler if we have a number for the density. Measure the volume, multiply by density, there's the mass. Do some knitting with gravity and off we go. If there's enough fuel that is. Ah yes, it's all coming back now.... * 😛 *
Posted