I know that we all come from different walks of life and jobs for that matter. This is why I have to ask this question. It’s plagued me for years and I’d like to have an answer. There has to be a physicist amoungs us.
The question is this… If you had a shrinking machine that could shrink anything down to say 1/87 scale , would it still weight the same. For instance a 300 ton locomotive shrunk down to 1/87 scale ??? Would it still weight the same ??? Hypatheticaly speaking if this could happen.
I figure i’ll get hosed for asking a silly question ,such as this, but go ahead…
Im no physicist, but it seems that it would make sense that the object would weigh the same. Even though you are making an object 1/87th its size, the density of the materials and the ammount of the material is not changing. That seems to make sense but idk.
I’m not a physicist but I DID stay at a Holiday Inn Express last night! It’s about mass. You reduce the volume of mass, the ‘weight’ or displacement of mass will reduce equally.
The weight of the object would shrink as well. In other words, if you were able to shrink a cubic foot of steel down to a cubic inch, it would only weigh 1/1728 of it’s original weight.
“Weight” would stay the same. By shrinking the item down, you’d be altering the density (mass per unit of volume).
The pair of new jeans that fit before they went through the wash still weigh the same, even though they don’t fit now because they shrunk in the wash. (Assuming that you didn’t enter a banana split eating constest since the last time you wore them.)
My parents will be back on Tuesday…they shall answer your question. They both teach it at the university…
Personally, I can’t decide. When I think about it, I get to the moolocules and stall. How much does the molocule weigh? Is it the same mass, even though it’s shrunk? Is it as Tracklayer said? I don’t know…I bet it’s a really hard question to answer.
My hot smoking TI BAII Plus tells me that a 300 ton locomotive - that’s 600,000 lubs - should weigh about 14.5 ounces if reduced to 87.1 raised to the 3rd power. How much does an HO scale locomotive weigh - the Navy song is Anchors Away but no one has ever been able to tell me how much an anchor weighs.
Old George Carlin gag:
Is that a U-Boat?
It’s no-a-my boat. Is it a you-boat!!!
Depends on what “magical” process does the shrinking. Weight is determined by the amount of matter or mass in an object - well, technically, it’s the resistance to gravitational attraction to another object. Shrinking by reducing the space in between the molecules doesn’t reduce the mass, so the weight’s the same. Shrinking by reducing the area of the electron orbits, though seriously destabilizing what you’re trying to shrink (remember this is “magical”) also does not remove any mass, so the weight is still same. If your magical process shrinks the particles themselves, or the particles within the particles, then who knows? Physicists don’t really know what gives matter its mass, though they currently postulate it’s a particle’s interaction with the theoretical Higgs field, so no one can yet say.
Most people here are familiar at least with the concept of a black hole. Shrinking a large star down to the size of a planet certainly does not decrease its mass, or there would be no “black hole effects.”
You’ll get the cube root of the mass, so it will weigh much less than 1/87th of the original. That is why there can be no such thing as the giant in Jack and the Beanstalk. The monster would not be able to support its own weight if it were ten times the dimensions of the average human.
When I was a kid in school, our math teacher put the giant question to us. The question was how much would a giant weigh that was ten times the size of an average six foot tall - 200 pound male football player. Of course most people answered 2,000 pounds, but that’s only in one dimension. I think the answer was 200,000 pounds… I think the formula is ten times the height by ten times the width by ten times the thickness. Please forgive me if I’m wrong. It’s been almost 35 years ago since I was a kid in school…
Selector has it right – the weight would be reduced according to the cube-root rule.
Thus, for any object reduced to a HO scale model:
length of object reduced by a factor of 1:87
weight of object reduce by a factor of 1:87 X 1:87 X 1.87
This is one reason why model railroaders sometimes have issues where model equipment is not as heavy as it should be relative to the prototype. Think of the average flatcar. In real life it is still heavy enough empty to not be affected by things that would derail the same car if it were a plastic model. That is why it is a good thing to use metal for flat and spine car models, as this compensates somewhat for the scale model weight deficit brought on by the cube-root rule.
Mike Lehman
Urbana, IL
(who is a historian of science, but not actually a scientist)
'[:)]
OK, I’m a real physicist. Of course, I’ve been out of school so long that things have changed some. Back in my day there were only 3 or 4 elementary particles to worry about. (Yeah, I played soccer with Isaac Newton.)
But, I’d say jsmaye hit the atom square in the nucleus with his answer. If this Incredible Shrinking Machine (“Honey, I shrunk the locomotive?”) works by compressing the space between the atoms and molecules, then the mass will stay the same, and the objects will shrink but retain their weight. If, on the other hand, the shrinking is done by removing atoms and molecules, then the mass (and therefore the weight) will shrink, as has been pointed out, by the inverse cube of the linear dimension. Another option would be to shrink the electron orbital shells, which would retain mass, but reduce the size of the object.
Saying, “Well, we’ll just reduce the space between the atoms and molecules,” or “We can shrink the electron shells,” isn’t particularly realistic. These things are the way they are because they must obey the laws of physics, chemistry and quantum mechanics. As you heat and cool things, they expand and contract very slightly from just this effect, but even cooling things down to absolute zero won’t actually reduce the size very much. This is primarily a physical, not chemical or nuclear, effect.