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Garden Gnome Tests Earth's Gravity
sciencehabit writes "Researchers have long hypothesized that objects weigh less at Earth's equator because the planet's spin and shape lessen gravity's pull there versus at the poles. Satellite accelerometers have confirmed this, but a digital scale manufacturer decided to test things the old-fashioned way. Enter the Kern garden gnome. When placed on a scale at the South Pole, the intrepid ornament weighed 309.82 grams versus 307.86 grams at the equator, a difference of 0.6%."
I buy my drugs at the North pole.
So it has come to this.
That should be more than enough for heavy metal arbitrage.
If video games influenced behavior the Pac Man generation would be eating pills and running away from their problems.
Nice to see some practical science that illustrates a point.
myke
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Next to the standard kilogram, there will be a standard garden gnome.
0.6% is not a small number. I'm looking forward to discussing the next international health survey and asking "Did you normalize your weights for gravitational variance?"
NB: The message above might reflect my opinion right now, but not necessarily tomorrow or next year.
I know that, whenever I see a garden gnome, I feel a powerful urge to use it to test gravity. Especially if there's a large asphalt or cement driveway nearby.
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Occupy the South Pole!
"When placed on a scale at the South Pole, the intrepid ornament weighed 309.82 grams versus 307.86 grams at the equator..."
The grams is a unit of mass, which is invariant depending on gravity. The metric unit of weight is the kilopond.
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Does it also test the Earth's travelocity?
(I'm so, so sorry. I'm a sick man. I need help.)
the mass of the earth is the same whether it's spinning or not. the spin causes centripetal acceleration, which is in the opposite direction of the acceleration due to gravity. i.e. the 'centrifugal force' cancels out a little bit of the 'gravitational force', but the gravity force itself is only slightly different because of shape, not because of the spin itself.
or am i missing something?
It's sometimes an acceptable shorthand to express a weight in grams, but not when that's the whole point of the story. The _mass_ in grams is (hopefully) not changing. The _weight_ in newtons (or any other dimensionally-correct unit you prefer) is what's changing.
If you're using a device that measures weight and reports it in grams, then you need to re-calibrate it against a known reference mass at each new location.
p.s. don't forget about buoyancy. Accurate measurements need to be done in a vacuum chamber.
Garden Gnomes just showed themselves to be more important to science than Creationalists and global-warming deniers.
how much was lost during transport?
You are allowed one more chocolate chip cookie at the Equator than on the South Pole.
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That's what they did.
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Does it also test the Earth's travelocity?
Imagine a travel agency called "Traspeed". It'd be like Hotwire or Priceline, filling unused seats on a flight and unused rooms in a hotel. Except you wouldn't even get to pick where your vacation will be, just "a ski resort" or "a beach resort" or "an amusement park" or the like. So you never know where you're going, but you know how fast you'll get there.
Dang it I was going to build a greenhouse at the pole and grow medicinal marijuana and sell it on the Internet. Now I can't as I'll lose too much money on customers at the equator.
We learned in school that the standard gravity is 9.83 m/s^2 at the poles and 9.78 m/s^2 at the equator. That was more than 15 years ago, so I would say it is a known fact and not a hypothesis?
Because it's not like anyone's been, say, calibrating pendulum clocks at different latitudes, ever.
Nice slashvertisement for Kern, though.
. . . and the equator Gnome had sweated off those extra grams . . .
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The earth's shape is a geoid, which is flattened compared to a sphere. Because the distance from center of mass to the surface is smaller at the poles than at the equator, gravity is stronger at the poles, and the weight of an equal mass is greater.
1) The object's mass
2) The object's theoretical weight difference at the different locations
3) The error bounds on the measurement.
Without any of this, I have no idea if this is shocking news, or merely expected. And I'm on slash dot, while it might be contained within the article, I don't come here to RTFA.
...
Will Kern blend?
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Afterwards, did they blast it into space?
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Why did they use a garden gnome? Simple! If you read slashdot a lot, you'll recall that large, perfectly spherical metal balls that weigh precisely 1KG are notoriously inaccurate and change weights on a whim, lol.
By the way, the temperature difference alone is enough to mess up the scale, let alone atmospheric pressure.
All I have to say is: no shit, Sherlock! This is news how, again?
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and sets in the west, if you were in a spaceship directly above the north pole looking down on earth which direction is the earth rotating? (counter-clockwise) what if you put a garden gnome at the north pole with one of those geeky propeller hats so the rotation of the earth gave it a slight lift and another gnome at the south pole with a geeky propeller hat so it has a slight lift too, (not sure where i am going with this but just thought i would throw it in the pot 0' gold)
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changes gravity.
i.e. they are specifically claiming that 'gravity is different due to the spin'. but the spin is only relevant in that the earth's "geoid" shape is thought to be due to the spin. the spin itself doesnt change how gravity works. at least not that i am aware of. if the earth stopped spinning all of a sudden, but remained a geoid... then the gravity at the poles wouldn't change, nor would the gravity at the equator. the only thing gone would be the centripetal acceleration due to spin. things would 'weigh less' because they lacked centripetal acceleration not because gravity suddenly changed.
an interesting question about your point is this - if you take stuff to the top of a mountain, does it weigh 'more' or 'less' than at sea level?
and if the earth sped up by a huge amount, things would 'weigh' a lot less. in fact, some things would go flying off into space... if earths outer edge somehow managed to reach escape velocity (in some unimaginable cataclysm). gravity itself wouldn't have changed though.
Dang, those gnomes get around.
Lacking <sarcasm> tags,
This sentence is completely without sense. Barring relativistic effects, the object's mass in grams remains constant. One of those masses is correct (possibly), the other is a measuring error introduced by a scale not calibrated correctly for local gravity. The actual discrepancy is in the weight of the object in Newtons. This is, like, middle-school physics stuff.
That's like using an iron yardstick to determine that one meter in summer is equal to about 1.005 meters in winter, and conclude that space itself expands and contracts.
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But wouldn't the column of air above the scale in the one region be a different weight than the other? That means that the starting '0' displayed on the scale would be different - thereby giving a false starting point to begin with. IOW if the scale were empty in one region it would disply '0' then when they took it to the other region - without any adjustments - when it had nothing on it, it would not display a '0' correct?
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Assuming they use the same counter weights at both locations, how do they get different results?
If they used one of those electric scales that measures the change in the length of a piece of metal, did they account for the scale shrinking due to the temperature difference?
0.6% seems like a large number, but since they don't mention the expected variation I have no way to tell if it is.
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It's warmer at the equator than at the poles, and everybody knows things weigh less when they heat up. That's why they expand.
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A garden gnome's weight in newtons or pounds may change depending on local gravity and acceleration. Its mass specified in grams does not change unless you add or remove material.
I once heard that the reason everything falls downwards is that everything that falls UPWARDS (or sideways) have long since disappeared into space, and have therefore not been able to breed. So everything that's still here on Earth has the "fall downwards"-gene still present.
Source: http://www.youtube.com/watch?v=8SNZuOHnFDk (In Swedish, but you get the idea.)
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Bathroom scales don't need to be as precise. In the United States, for example, they're marked "not legal for trade". But perhaps it's calibrated for the center of the populated portion of the state or territory where it is sold, and its internal kgf to kg conversion is indeed accurate to 0.1% within that area. For example, scales shipped to the Northern Territory would be calibrated differently from scales destined for New South Wales or Victoria.
Has an equivalent test been done with KDE?
Earth's spin affecting weight measurement is hundred year old, settled science. In fact, even the direction of travel has a measurable effect:
http://en.wikipedia.org/wiki/E%C3%B6tv%C3%B6s_effect
But, hey, science is all about reproducible results right? Nice to see they reproduce so well.
The gnome was of little use ; they could have used an elf instead !
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