eggtimer

[p1j1r1]

if an eggtimer was sat on a set of scales with all the sand in the bottom, and it was turn around so the sand started flowing, would it weigh more, less or same than when it was originally sat there ?

[zig.zag]

this must be a trick question lol

[ll_billym]

It would weigh less as the bulk of it is further from the earth hence less gravitational pull hence less weight.

[gen2]

It will weigh less.
As each grain enters free-fall, it is no longer exerting a force on the egg-timer walls, and hence not on the scales. The overall weight will be reduced by the weight of the stream of sand in free-fall.

[Clanad]

Unless the sand is enclosed within the 'timer' in a vacuum, the "free fall" of the sand makes no difference. It's the old story of "does a truck full of pigeons weigh less if all the pigeons were made to fly". Answer? No. The pigeons (and the grains of sand) exert their weight on the air which transmits the weight (more accurately, mass) to the bottom of the timer.
However, II_billym is on to something and its called the inverse square law.. Simply stated, if the distance between two objects were to increase by a factor of 10, the gravitational influence exerted by each object upon the other would decrease by a factor of 100. So, the variable here is the small distance between the volume of sand that was originally at rest nearer the center of the Earth's mass is now a minute distance further away... hence an incalcuable (well, not really) small loss of mass until it drains back to the original, lower position...

[Schutzengel]

A bit like the question - Does a ton of feathers weigh less than a ton of bricks.

[steveb]

or what weighs more an ounce of gold or an ounce of sugar

[theprof]

steveb, an ounce of gold weighs more than an ounce of sugar.

This is because gold is weighed in troy ounces whilst sugar is measured in avoirdupois ounces.

A troy ounce is about 31.11 grams whereas an avoirdupois ounce is 28.35 grams.

[steveb]

exactly, but a pound of sugar weighs more, lol. sorry ive taken this off topic.

[theprof]

A pound of sugar weighs more than what? If you're still referring to gold, no it does not weigh more than a pound of gold. Multiply up the unit size of one commodity and you have to multiply up the unit size of the other.

[steveb]

but there are only 12 troy ounces in a troy pound, and 16 avoirdupois ounces in an avoirdupois pound, 373 grams compared to 454.

[theprof]

Steveb, in your original post ,you said "what weighs more an ounce of gold or an ounce of sugar", You made no mention of pounds, stones or any other avoirdupois mass unit in the post.

As I said, an ounce of gold is 31.11g whereas an ounce of sugar is 28.35g.

You did not mention pounds in your original post and therefore the fact that there are only twelve troy ounces to a troy pound as opposed to sixteen avoirdupois ounces in an avoirdupois pound is totally irrelevant.

Bear in mind that if you had said "what weighs more a pound of gold or a pound of sugar" my answer would have been different.

[steveb]

right...ok

[Bert]

Schutzengel wrote:
A bit like the question - Does a ton of feathers weigh less than a ton of bricks.
No, it's not a bit like that question. It is like the question of the lorryload of birds. The problem with the sand is what happens to the weight of the sand that is between the 'waist' of the eggtimer and the sand in the bottom half of the eggtimer. We can imagine the eggtimer to be evacuated of air, so that the weight of the sand in flight cannot be transmitted to the base of the eggtimer, in contrast to the flying birds. I would not want to work it out, but I imagine that the impact of the sand hitting the base of the timer would be exactly enough to compensate for the 'loss' of its weight during the fall.