Weight question

I saw a program on TV that weighed a person of weight X. Then they weighed a McDonalds Burger, weight Y. Then the person ate the burger and the weighed him once more. His weight after eating the burger wasn't NEARLY close to X+Y. It was in fact very close to his original weight. Why is that. They showed the experiment, but not an explination. Could somebody shed some light on the subject?

ye sits quite simple, a Macdonalds burger, whatever, hits the stomach much in the same way that a meteorite hits the atmosphere and its burns up on entry leaving no trace, thus the mans weight remains the same.

Originally posted by ysterbaard
I saw a program on TV that weighed a person of weight X. Then they weighed a McDonalds Burger, weight Y. Then the person ate the burger and the weighed him once more. His weight after eating the burger wasn't NEARLY close to X+Y. It was in fact very close to his original weight. Why is that. They showed the experiment, but not an explination. Could somebody shed some light on the subject?

Two weights added together will certainly be the sum of the weights. Mass isn't destroyed or created in the process. (Unless we're talking about nuclear recations, which is not the case here.)

So you have a person and a Burger. When he ate this, did he breath? There we have mass in and mass out in the form of air. Breath contains water. Did he sweat? Sweat weighs. Did he ate all the Burger or did he left some residues? And so on.

If you measure every substance, solid, liquid or gas form, then you will also have a total equivalence.
(Weight of Person) + (weight of Burger) equals exactly weight of (Person + Burger).

I talk about weight, but I should really talk about mass. But in the same gravitational field it doesn't really matter.

Yeah I guess that answers the question. They performed the experiment in a 'sloppy' way. In other words the environment was not completely sealed off, so breath, sweat etc. was not accounted for. Residues of the burger as well. But what I was looking for is that in a 'perfect' experiment the two masses when combined shoud be equal to the sum of the two apart. The difference in weight should only occur after excretion of the remains of the burger.

Originally posted by ysterbaard
Yeah I guess that answers the question. They performed the experiment in a 'sloppy' way. In other words the environment was not completely sealed off, so breath, sweat etc. was not accounted for. Residues of the burger as well. But what I was looking for is that in a 'perfect' experiment the two masses when combined shoud be equal to the sum of the two ap ...[text shortened]... rt. The difference in weight should only occur after excretion of the remains of the burger.

Right.

Another experiment made once was to measure the wight of the soul. A person before his death was weighed carefully and after the death, when the soul was supposed to have left the body, it was weighed again. The difference between the two was the weight of the soul. So they thought.

They did the same experiment with a dog, and, guess what, there was no difference. This is a proof that dogs have no souls. So they thought.

However, if we repeat this experiment carefully with all things accounted for, in a strictly scientific way, we cannot measure any defference in weight before and after the death. Hence, the soul doesn't weigh anything, or does not exist.

How much did the soul weigh? 21 grams.
What year did the experiment take place? 1907.
Was the experiment successful? Yes, they got the result they wanted.
If not? They would have done the experiment again.

Originally posted by ysterbaard
I saw a program on TV that weighed a person of weight X. Then they weighed a McDonalds Burger, weight Y. Then the person ate the burger and the weighed him once more. His weight after eating the burger wasn't NEARLY close to X+Y. It was in fact very close to his original weight. Why is that. They showed the experiment, but not an explination. Could somebody shed some light on the subject?

It probably has something to do with the scale they used. According to the nutrition calculator at www.mcdonald.ca, the average Big Mac weighs 209 grams or 0.209 kg (or about 7.4 oz., just under half a pound). According to a 2004 report from the Centre for Disease Control (http://www.cdc.gov/nchs/data/ad/ad347.pdf) the average weight of a male in the United States is 190 lbs or 86.4 kg. Therefore, the average US male weighs about 86.4 kg / 0.209 kg = 413 times as much as a Big Mac. Typically you need a very accurate scale to be able to measure a spread of 3 orders of magnitude precisely. I don't think bathroom scales that are designed to weigh things in the 50-500 lbs range will measure a half-pound particularly accurately, let alone the error in reading the measurement off a scale with 5-lbs or even 1-lbs gradations.

Originally posted by PBE6
It probably has something to do with the scale they used. According to the nutrition calculator at www.mcdonald.ca, the average Big Mac weighs 209 grams or 0.209 kg (or about 7.4 oz., just under half a pound). According to a 2004 report from the Centre for Disease Control (http://www.cdc.gov/nchs/data/ad/ad347.pdf) the average weight of a male in the United S ...[text shortened]... let alone the error in reading the measurement off a scale with 5-lbs or even 1-lbs gradations.

I think that this is the correct explanation. Also, did they use one scale to weigh the person and a different scale to weigh the burger?

Originally posted by ysterbaard
Yeah I guess that answers the question. They performed the experiment in a 'sloppy' way. In other words the environment was not completely sealed off, so breath, sweat etc. was not accounted for. Residues of the burger as well. But what I was looking for is that in a 'perfect' experiment the two masses when combined shoud be equal to the sum of the two ap ...[text shortened]... rt. The difference in weight should only occur after excretion of the remains of the burger.

Besides that, they could have been using a household scale which is just not accurate enough to register the difference. If you have an accurate scale, say accurate to within a gram or so, and you weigh the person, then have him just HOLD the hamburger, it will for sure register the change in weight. It will not change if he then eats it, sweating or whatever will register a change if it is accurate enough. It WILL add up.

Originally posted by robbie carrobie
ye sits quite simple, a Macdonalds burger, whatever, hits the stomach much in the same way that a meteorite hits the atmosphere and its burns up on entry leaving no trace, thus the mans weight remains the same.

I think it could be that the burgers are so heavy that they are still accelerating downwards when the subject gets on the scales.

Originally posted by sonhouse
Besides that, they could have been using a household scale which is just not accurate enough to register the difference. If you have an accurate scale, say accurate to within a gram or so, and you weigh the person, then have him just HOLD the hamburger, it will for sure register the change in weight. It will not change if he then eats it, sweating or whatever will register a change if it is accurate enough. It WILL add up.

I think you are right here.

The scale has to be sensitive enough to register the weight of the hamburger. Then it would add up.