Offline edby

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Re: Increased gravity at the poles?
« Reply #80 on: November 14, 2018, 07:37:19 PM »
Besides that, if the earth were under a constant acceleration (UA) Kern wouldn't have to compensate their equipment for different locations.  I'm thinking that this isn't another government conspiracy.  I think the bigger worry would be that when I buy the next batch of unobtainium at the hardware store I'll have to watch that the salesman doesn't have his thumb on the scale.
Right, but Tom thinks the compensation is necessary because of the difference in atmospheric pressure between different locations. Presumably we even need to compensate for the same location. E.g. if it was 980mb in London last week, and if it is 1040mb in London this week, my weight will increase by 6%. Thus if you weighed 170lb last week, you will weigh 180lb this week. Does that make more sense?

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Offline stack

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Re: Increased gravity at the poles?
« Reply #81 on: November 14, 2018, 07:38:39 PM »
Which expert opinion should we believe?

I'm thinking a neutral neighbor.

Apparently the Canadians take their scales and gravity tolerance/compensation/calibration very seriously. They have a whole government application process to make sure specific location gravity is taken into account:

"Calculate gravity tolerance for scales

The gravity tolerance application calculates the change in gravity between two locations in Canada. This helps you find out whether a non-automatic weighing device can be inspected in one geographic location in Canada, and then put into service in another without requiring readjustment."

https://www.ic.gc.ca/eic/site/mc-mc.nsf/eng/lm04890.html

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Offline RonJ

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Re: Increased gravity at the poles?
« Reply #82 on: November 14, 2018, 07:51:16 PM »
Probably some consumer group got mad and thought that they were being screwed somewhere along the line so the government had to step in an establish a standard that could be enforced. That's one of the reasons the Somigliana Formula is important and is used by people to compensate their equipment for a change in latitude.   

All the 'confusion' perpetrated by an 'unknown' entity on here can really stir the pot and get the posts flying.  Do you suppose that is really an accident?
   
« Last Edit: November 14, 2018, 08:02:49 PM by RonJ »
You can lead flat earthers to the curve but you can't make them think!

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Offline Tom Bishop

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Re: Increased gravity at the poles?
« Reply #83 on: November 14, 2018, 08:11:49 PM »
A scale that measures the weight of the atmosphere has already been invented. It is called the "barometer".

Air pressure does not affect the scale trivially. See the following illustration and text:

https://www.artofmanliness.com/articles/fair-or-foul-how-to-use-a-barometer/

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Air pressure decreases as altitude increases.

Atmospheric pressure — or barometric pressure — is simply the weight of the air at ground level. It’s a little easier to understand when you think about the concept of water pressure first. As you get deeper in water, the pressure increases. This is because as you descend, the built up weight of the water on top of you increases. In 1 foot of water, you have the weight of that foot of water pressing down on you. In 2 feet of water, you have the weight of an extra foot of water pressing on you. It’s quite logical, really.
« Last Edit: November 14, 2018, 08:14:30 PM by Tom Bishop »

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Offline stack

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Re: Increased gravity at the poles?
« Reply #84 on: November 14, 2018, 08:26:38 PM »
A scale that measures the weight of the atmosphere has already been invented. It is called the "barometer".

Air pressure does not affect the scale trivially.

Sure, but are we talking about being at 18,000' versus sea level or at a pole versus the equator?

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Offline Tom Bishop

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Re: Increased gravity at the poles?
« Reply #85 on: November 14, 2018, 08:45:40 PM »
A scale that measures the weight of the atmosphere has already been invented. It is called the "barometer".

Air pressure does not affect the scale trivially.

Sure, but are we talking about being at 18,000' versus sea level or at a pole versus the equator?

The difference between those two locations isn't necessarily as radical.

The point is that farcical promotional stunts are being presented as fact, without control for other variables.

Offline edby

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Re: Increased gravity at the poles?
« Reply #86 on: November 14, 2018, 09:01:22 PM »
The point is that farcical promotional stunts are being presented as fact, without control for other variables.
How is this relevant to your claim that change in atmospheric pressure is the primary cause of the 0.5% increase in weight at the pole? And how do you meet the objection that the same change in atmospheric pressure in London has no such impact on weight? Something has to give here, Tom.

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Offline Bobby Shafto

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Re: Increased gravity at the poles?
« Reply #87 on: November 14, 2018, 09:07:19 PM »
A scale that measures the weight of the atmosphere has already been invented. It is called the "barometer".
Not quite, but it's a good point. You can derive a measure of weight of the atmosphere from a barometer reading. You can also derive a buoyant force figure from a barometer reading.

When air pressure goes up, the weight of the atmosphere does too. But then so does the buoyant force.
When air pressure goes down, the weight of the atmosphere is less, but then so is the buoyant force.

It's an error to apply the weight of the atmosphere alone. Air pressure (measured by a barometer) is in all directions. There's a vector down (weight from above pushing down) and a vector up (buoyancy pushing up from below). It's the net that contributes to an object's weight.

Forces from the side cancel out, but if they (and above/below forces) cause changes in volume of the object, then that changes the net air pressure equation also.

Flatly stating air pressure is the reason for an object having greater measured weight at the poles than at the equator as the 2nd post in this topic claims is flawed because it ignores buoyancy (as does stating that a barometer measures weight of the atmosphere without acknowledging it measures the opposing forces as well). 


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Offline RonJ

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Re: Increased gravity at the poles?
« Reply #88 on: November 14, 2018, 10:05:49 PM »
Let’s say you take a friendly Gnome to the South Pole and weigh him.  You get the reading of 309.82 grams.  Now you are a total skeptic and are worried about the air pressure altering the real reading, so you wave your magic wand and suck out all the air in the atmosphere.  Now the effects of buoyancy of the air go away and the friendly Gnome now only weighs 309.74 grams. You are not measuring the Gnome against a vacuum anyway, only against the earth’s gravity and a small variation in atmospheric pressure.   You can do all the ‘rope-a-doping’ you want, but the observed facts will remain the same.  The biggest effects on the weight of the Gnome will be the uneven force of gravity on the earth.  Atmospheric effects are negligible and is like the water level effects of ‘pissing in a pool’.   Of course if you don’t believe in the earth’s gravity the whole thing is moot and you have to come up with another explanation for the well documented and observed measurements. 
You can lead flat earthers to the curve but you can't make them think!

LoveScience

Re: Increased gravity at the poles?
« Reply #89 on: November 15, 2018, 11:17:31 AM »
Basing my answer purely on the text of the original question, yes you would experience an increased gravitational effect at the poles because the effect of centrifugal force (acting to oppose gravity which gives us our impression of weight) diminishes.

Therefore your weight would be greatest at the equator and least at the poles.

LoveScience

Re: Increased gravity at the poles?
« Reply #90 on: November 15, 2018, 11:21:15 AM »
Sorry! disregard previous.  I got distracted while typing.  Your weight would be greatest at the poles (due to a lack of centrifugal force since you are effectively spinning on the spot if standing exactly on rotation axis) and least at the equator because the effect of centrifugal force is greatest at the equator.

Offline edby

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Re: Increased gravity at the poles?
« Reply #91 on: November 15, 2018, 11:50:40 AM »
Sorry! disregard previous.  I got distracted while typing.  Your weight would be greatest at the poles (due to a lack of centrifugal force since you are effectively spinning on the spot if standing exactly on rotation axis) and least at the equator because the effect of centrifugal force is greatest at the equator.
Well it would be on the globe-earth hypothesis. However on the FE Universal Acceleration hypothesis, where the world's surface is an approximately flat plane, accelerating upwards at 9.81 ms^2, 'gravity' would be constant at all locations.

Tom's hypothesis above is that the measured differences are due to changes in atmospheric pressure, not gravity.

Offline edby

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Re: Increased gravity at the poles?
« Reply #92 on: November 15, 2018, 11:59:15 AM »
Let’s for the moment concede Tom’s objection to relative (i.e. spring based) gravimeters, and consider how absolute gravimeters work. This outlines how an absolute gravimeter works.

Quote
The A10 operates by using a free-fall method. An object is dropped inside a vacuum chamber and its position is monitored very accurately using a laser interferometer.

Note that if the object is dropped in a vacuum, any objection about air pressure is irrelevant.

If you look at research using the A10, it is accurate to within a few microgals. A gal (named after Galileo) is a unit of acceleration defined as 1 centimeter per second squared (1 cm/s2). One microgal is clearly a very small amount, so absolute gravimeters are extremely high precision instruments.
Relative gravimeters are mostly used for work in the field, due to expense and portability. However they can be calibrated to an absolute gravimeter, as the paper below explains.
Quote
https://www.geos.ed.ac.uk/~hcp/gravity/grav_intro.pdf It is possible to build an instrument that measures g directly. Such an instrument is called an absolute gravity meter and is large, unwieldy and expensive. For field surveys it is more usual to use a relative gravity meter. These are cheaper, smaller and more robust. But they do not measure the absolute value of g. They can only measure the differences in g between one place and another. Relative gravity meters are essentially a mass hung on a spring: if you go to somewhere where gravity is a bit larger, the spring stretches a bit more. The extra stretch is tiny: to measure it, we pull on the spring with a micrometer screw to restore the mass to the original position. Levers are used to make the system more sensitive and the whole mechanism is enclosed in a temperature-controlled box to prevent changes in temperature from affecting the results.

If Tom is correct, we have to make implausible assumption that while masses of research has been done using both forms of gravimeter, no one has bothered to check whether acceleration due to gravity is higher at the poles.

LoveScience

Re: Increased gravity at the poles?
« Reply #93 on: November 15, 2018, 01:25:17 PM »
Quote
Well it would be on the globe-earth hypothesis. However on the FE Universal Acceleration hypothesis, where the world's surface is an approximately flat plane, accelerating upwards at 9.81 ms^2, 'gravity' would be constant at all locations.


Well in that case that is another point in favour of the globe-earth hypoethesis then. I guess it all depends on your own point of view. Ignoring Earth rotation and any effects due to the atmosphere. On a body of the mass of the Earth, gravitational acceleration is a constant as it only depends on mass (F=mg) to quote Newtons 2nd Law.
« Last Edit: November 15, 2018, 01:28:13 PM by LoveScience »

Offline edby

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Re: Increased gravity at the poles?
« Reply #94 on: November 15, 2018, 04:45:47 PM »
See the table below which I sourced from http://www.physics.montana.edu/demonstrations/video/1_mechanics/demos/localgravitychart.html

There are a couple of anomalies, but it follows a straight line trend implying a difference of 0.5% between observed acceleration at equator and poles.

I don't know how the numbers were computed. If using a relative gravimeter, then perhaps Tom is right, although it defies belief that the smart people who devised these experiments missed something as obvious as atmospheric pressure. If an absolute gravimeter, then Tom is flat out wrong, and UA with it.

City, Acceleration, Abs lat
Quito, 9.7724, 0.1807
Singapore, 9.7814, 1.3521
Bogota, 9.7799, 4.711
Djakarta, 9.7814, 6.1805
Caracas, 9.7829, 10.4806
Lima, 9.7829, 12.0464
Manila, 9.7844, 14.5995
Guatemala City, 9.7844, 14.6349
Brasilia, 9.7889, 15.8267
La Paz, 9.7844, 16.4897
Mexico City, 9.7799, 19.4326
Port Louis, 9.7859, 20.1609
Hong Kong, 9.8099, 22.3964
Riyad, 9.7904, 24.7136
Taipei, 9.7904, 25.033
Johannesburg, 9.7919, 26.2041
Manamah, 9.7904, 26.2285
Kuwait, 9.7919, 29.3117
Panama City, 9.7814, 30.1588
Dallas, 9.7949, 32.7767
Baghdad, 9.7964, 33.3152
Santiago, 9.7979, 33.4489
Atlanta, 9.7964, 33.749
Sydney, 9.7979, 33.8688
Beirut, 9.7964, 33.8938
Rabat, 9.7964, 33.9716
Los Angeles, 9.7979, 34.0522
Buenos Aires, 9.7979, 34.6037
Montevideo, 9.7964, 34.9011
Mishima, 9.7979, 35.1184
Nicosia, 9.7979, 35.1856
Tunis, 9.7799, 36.8065
San Jose, 9.7829, 37.3382
Seoul, 9.7994, 37.5665
San Francisco, 9.7994, 37.7749
Athens, 9.8009, 37.9838
Lisbon, 9.8039, 38.7223
Ankara, 9.8024, 39.9334
Philadelphia, 9.8024, 39.9526
Madrid, 9.8024, 40.4168
New York, 9.8024, 40.7128
Wellington, 9.8039, 41.2865
Chicago, 9.8024, 41.8781
Detroit, 9.8039, 42.3314
Boston, 9.8039, 42.3601
Toronto, 9.8054, 43.6532
Bucharest, 9.8054, 44.4268
Ottawa, 9.8069, 45.4215
Montreal, 9.8069, 45.5017
Bern, 9.8084, 46.948
Budapest, 9.8069, 47.4979
Vienna, 9.8099, 48.2082
Vancouver, 9.8099, 49.2827
Prague, 9.8114, 50.0755
Brussels, 9.8114, 50.8503
Dusseldorf, 9.8129, 51.2277
London, 9.8144, 51.5074
Swider, 9.8159, 51.8986
Amsterdam, 9.8129, 52.368
Copenhagen, 9.8159, 55.6761
Stockholm, 9.8189, 59.3293
Oslo, 9.8189, 59.911491
Helsinki, 9.8189, 60.1699
Anchorage, 9.8189, 61.2181




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Offline RonJ

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Re: Increased gravity at the poles?
« Reply #95 on: November 15, 2018, 05:32:46 PM »
A relative or absolute gravimeter really doesn't matter.  In the worst case the measurements obtained are down in the millionths category of whatever measurement units you happen to be talking about.  There are gravimeters used on ships and on aircraft.  All this equipment has been designed and used by scientists and engineers and all the possible corrections have been accounted for.  The oil companies use this equipment in their prospecting efforts along with the mining companies.  If the technology didn't work they wouldn't be buying this equipment.  Now with the new MEMS technology I would expect to see some useful equipment available in you iPhone sometime in the future.  I don't know what it would be used for, however.  A story I saw was that a company had a absolute gravimeter so sensitive that they could tell when the snow was removed off the roof of the building they were in.  The bottom line is everything is down to a 'gnats ass' and all you are arguing about is how many pimples are on that ass.  The Kern scale experiment was a promotional thing and not a real scientific experiment.  That doesn't mean that the results are not valid.  The results are just are not anywhere as accurate as they could be if the proper equipment was brought to the scene. Many absolute gravimeters (from many countries) were brought together at a single location and the results compared.  The arguments were down to a millionth of a millionth.  These gravimeters are spread out all over the world and are producing readings on a regular basis.  No matter what UA, is not a viable argument unless it can be reworked to explain all the well documented results from scientists from countless countries that have measured a variation in the earth's gravity and can be explained by the rotating round earth paradigm. 
You can lead flat earthers to the curve but you can't make them think!

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Offline Tom Bishop

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Re: Increased gravity at the poles?
« Reply #96 on: November 15, 2018, 05:41:36 PM »
If you want to claim accuracy on an experiment then you need to demonstrate that all variables were accounted for, and that it was properly controlled. All variables were not accounted for with the gnome and spring scale experiment.

Nonetheless, no gravimetric discrepancy would disprove UA. You would need to show that there are no slight gravimetric disturbances above or below the earth. This is why this topic is a dead end discussion-wise.
« Last Edit: November 15, 2018, 05:43:34 PM by Tom Bishop »

Offline edby

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Re: Increased gravity at the poles?
« Reply #97 on: November 15, 2018, 05:43:08 PM »
If you want to claim accuracy on an experiment then you need to demonstrate that all variables were accounted for. All variables were not accounted for with the gnome and spring scale experiment.

Nonetheless, no gravimetric discrepancy would disprove UA. You would need to show that there are no slight gravimetec disturbances above or below the earth, and this is why this topic is a dead end discussion-wise.
This is what logicians call the 'nuclear option'. Whatever carefully observed observation is produced, will always be open to the objection that there is some completely unknown force which distorts the observations. It could be leprechauns, for example.

What evidence if any would you accept as 'disproving' UA then Tom? Also, if you would refuse to accept any evidence whatsoever o/a of your faith in UA, how is your belief distinguishable from a religious or superstitious belief?
« Last Edit: November 15, 2018, 05:44:44 PM by edby »

Offline JCM

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Re: Increased gravity at the poles?
« Reply #98 on: November 15, 2018, 05:47:55 PM »
If you want to claim accuracy on an experiment then you need to demonstrate that all variables were accounted for. All variables were not accounted for with the gnome and spring scale experiment.

Nonetheless, no gravimetric discrepancy would disprove UA. You would need to show that there are no slight gravimetric disturbances above or below the earth. This is why this topic is a dead end discussion-wise.

You are going to dismiss Edby’s data showing a straight trend line with latitude just like that?  It’s a trend line to 4 decimals! What possible other variations could create that trend line? You are the one discounting the data, you need to show what’s wrong with that data. 

Re: Increased gravity at the poles?
« Reply #99 on: November 15, 2018, 05:50:15 PM »
If you want to claim accuracy on an experiment then you need to demonstrate that all variables were accounted for, and that it was properly controlled. All variables were not accounted for with the gnome and spring scale experiment.

Nonetheless, no gravimetric discrepancy would disprove UA. You would need to show that there are no slight gravimetric disturbances above or below the earth. This is why this topic is a dead end discussion-wise.
Have you discussed your concerns with any scientific institutions?