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Sunshine

Does The moon affect your weight??

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Here's one to crack your nut open with lol, if even by an immeasurable amount, as the moon is passing above you in the sky will one weigh less?. Ok i understand that sounds crazy but, everything on earth is affected by the moon'sgravitational influence. This is most easily demonstrated as you all know, by tidal changes (most obvious effect) among others, having said that, whatever can be raised by its influence should be perceived as being lighter when measured.I imagine a person with a big magnet strapped to their head, feet on the ground, now pass another magnet above their head, exerting an attractive force equal to 1KG, if you were to weigh that person at that time the scale would most definitely register their weight as being 1KG less. 

I realize that gravity is not a force as is commonly perceived, there is no force attracting bodies together, they are falling into a distortion caused in the fabric of spacetime by the mass of another body. I wanted to clear that up to save time later, regardless of how you want to look at it, we are just as affected by the moons passing as is the ocean. Therefore,  that effect must present itself in some way that can be measured, the only parameter i could think of is ones weight if such a small amount is measurable since the amount of influence would be directly proportional to the mass of the earth, the person, and the moons mass no?? 

Alright fire away!

 

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All i can say is Chocolate is directly proportional to my mass.

On a serious note it is an interesting question.

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My guess without any knowledge of the science behind it is No because the scales would also be affected? :) 

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The gravitational pull of the Moon from that distance would be tiny.  But gravitational effects are more noticeable here on Earth.  It is commonly thought that if you go below ground, you would weigh more through being closer to the centre of the Earth.  The opposite is true however, because the mass above you pulls in the opposite direction.  Ultimately, at the centre of the Earth, your weight would be zero.

Doug.

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Yes indeed.

We can "measure" it by measuring acceleration of falling body on the surface of the earth. We will get one value when Moon is above the falling body, and we will get another value when Moon is directly on the opposite side (behind the earth in relation to falling body).

Just for comparison, let's do some equations.

g on surface of the earth is given as

9.80665 m/s^2

Let's do the same calculation when Moon is above. g_moon = G*M/r^2, g_moon= 6.67408 * 10^-11 *  7.34767309 * 10^22 / (3.84 * 10^8)^2

So in exponents we have -11, 22 and 16, but that is dividing so it's a minus sign, and total then is 10^-5 and rest when put into calculator

~3.325667 * 10^-5

So value is about 300000 less than that of acceleration due to earth gravity.

For person of about 100Kg, difference would be about 0.3g

Average person has weight difference about 5g between inhale and exhale (about 4l of air having 1.2g each), so moon influence on us is really hard to measure.

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1 hour ago, vlaiv said:

Yes indeed.

We can "measure" it by measuring acceleration of falling body on the surface of the earth. We will get one value when Moon is above the falling body, and we will get another value when Moon is directly on the opposite side (behind the earth in relation to falling body).

Just for comparison, let's do some equations.

g on surface of the earth is given as

9.80665 m/s^2

Let's do the same calculation when Moon is above. g_moon = G*M/r^2, g_moon= 6.67408 * 10^-11 *  7.34767309 * 10^22 / (3.84 * 10^8)^2

So in exponents we have -11, 22 and 16, but that is dividing so it's a minus sign, and total then is 10^-5 and rest when put into calculator

~3.325667 * 10^-5

So value is about 300000 less than that of acceleration due to earth gravity.

For person of about 100Kg, difference would be about 0.3g

Average person has weight difference about 5g between inhale and exhale (about 4l of air having 1.2g each), so moon influence on us is really hard to measure.

I knew a number cruncher would make short work of the question, good job of quantifying it.

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Ref Vlaiv:  Average person has weight difference about 5g between inhale and exhale (about 4l of air having 1.2g each)

As our lungs are always open to the air, there is no weight change.
We simply redistribute our mass between collapsed and extended ribs.

In a closed system, there is a difference. If you take a deep breath, block your airway then compress your chest, the pressure in your lungs increases.
The mass/unit volume in your lungs is therefore higher, so you weigh a little more.
DO NOT try this at home! Crushing your chest can cause life threatening injury.
An analogy is a bottle weighs the same whether the cap is loose or tight.

It is much easier to understand these changes when scuba diving.
When you inhale a 4 litres of air, your buoyance changes by the water mass displaced (5Kg) minus air mass inserted (5g).
With correct buoyancy control you can make small ascents and descents by breath control only.

If you were rotated rapidly on a turntable then the state of your chest might be able to be measured by the speed changes, or changes in energy input to maintain speed.
This being a consequence of (expanding chest) mass moving away from the centre of rotation when inhaling.

Back to the original question.
If you are on scales with a spring or other bendy measuring device, you weigh less when the moon is overhead.
If you are on a balance (like those seen in clincs) your weight is compared to lumps of metal.
Both you and the metal are equally affected by the moon, you therefore weigh the same.

The chocolate mentioned is naother matter.
If you stuff yourself with a large mass of chocolate, like 1Kg in an hour, then you cannot possibly digest it fully and absorb all the fat.
The rule of mass being proportional to chocolate intake is only valid for low intakes.
In other words, stuffing yourself silly with chocolate does not pile on the pounds (sorry kilogrammes).

 

Some of the above is absolute rubbish. Some is valid science. Some is - well - inbetween.
Have fun separating the good stuff from the rubbish.

 

 

 

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8 minutes ago, Carbon Brush said:

Ref Vlaiv:  Average person has weight difference about 5g between inhale and exhale (about 4l of air having 1.2g each)

As our lungs are always open to the air, there is no weight change.
We simply redistribute our mass between collapsed and extended ribs.

In a closed system, there is a difference. If you take a deep breath, block your airway then compress your chest, the pressure in your lungs increases.
The mass/unit volume in your lungs is therefore higher, so you weigh a little more.
DO NOT try this at home! Crushing your chest can cause life threatening injury.
An analogy is a bottle weighs the same whether the cap is loose or tight.

It is much easier to understand these changes when scuba diving.
When you inhale a 4 litres of air, your buoyance changes by the water mass displaced (5Kg) minus air mass inserted (5g).
With correct buoyancy control you can make small ascents and descents by breath control only.

If you were rotated rapidly on a turntable then the state of your chest might be able to be measured by the speed changes, or changes in energy input to maintain speed.
This being a consequence of (expanding chest) mass moving away from the centre of rotation when inhaling.

Back to the original question.
If you are on scales with a spring or other bendy measuring device, you weigh less when the moon is overhead.
If you are on a balance (like those seen in clincs) your weight is compared to lumps of metal.
Both you and the metal are equally affected by the moon, you therefore weigh the same.

The chocolate mentioned is naother matter.
If you stuff yourself with a large mass of chocolate, like 1Kg in an hour, then you cannot possibly digest it fully and absorb all the fat.
The rule of mass being proportional to chocolate intake is only valid for low intakes.
In other words, stuffing yourself silly with chocolate does not pile on the pounds (sorry kilogrammes).

 

Some of the above is absolute rubbish. Some is valid science. Some is - well - inbetween.
Have fun separating the good stuff from the rubbish.

 

 

 

I'm a bit confused with all of this, since argument mixes density (mass/unit volume) with mass.

I was referring to a simple school example - of weighing two balloons on scales, one inflated, one deflated.

Therefore, if person inhales - they are more heavy :D. I don't think it matters if you close your mouth or not. For the sake of argument, let's suppose that you want to push a person (accelerate) that has air in the lungs, but is otherwise in vacuum (no air resistance). When you push that person you are pushing the mass of person and the mass of air inside their lungs (again let's imagine air stays there although person is in vacuum). You are accelerating total mass, so you measure total mass.

 

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A balloon that is under pressure (well inflated) will weigh slightly more than one that is not under pressure.

Back to a scuba example.

Aluminium air tanks, when full (200bar) sink. When going on towards empty (50bar) they float.

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