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Q & A: Tipping the scales in outer space

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Most recent answer: 10/22/2007
Q:
whats the difference between mass and weuight in outer space???
- aleka (age 15)
benjamin n cardozo hs, ny, usa
A:
Aleka,
What is the difference between mass and weight? Mass is the measure of how much 'stuff' something has in it. The more 'stuff' something has, the more mass it has.
Weight, however, is a measure of how much something is pushing on something else.. The difference between the two is often confused here on Earth because we tend to equate them since we measure mass and weight the same way. We measure weight by placing something on a scale. The scale tells us how much the object pushing against it. Since the Earth's gravity pulls on each little piece of mass the same, the mass is easy to figure out from the weight. For instance, if one rock on a scale weighs 5 pounds, and another weighs 10 pounds, we know that the second rock had twice as much mass, there was twice as much 'stuff' there, because it had twice as much force (weight) pushing against the scale.
However in space, we do not feel gravity like we do on Earth. If an astronaut touches a scale in space, the astronaut will have no weight because there is no force pushing the astronaut against the scale. But the astronaut is still made of stuff, so the astronaut still has mass.
So the difference between mass and weight, in space or anywhere, is that mass is the amount of 'stuff' something has, and weight is how much something pushes against something else.

I hope this answers your question.


math dan

(published on 10/22/2007)

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