1. Which weighs more, an ounce of gold or an ounce of cotton ? a. gold b. cotton c. they’re both one ounce, so they both weigh the same 2. Which weighs more, a pound of gold or a pound of cotton ? a. gold b. cotton c. they’re both one pound, so they both weigh the same I’ll post the answers and explanations later.
Gold weighs more for both. Gold is measured in troy ounces, and cotten in avoir du poids. There are 16 avp ounces in a troy pound, so a troy ounce is more than an avp ounce. I might have some of my French wrong, but this is the general idea. Of course, this is a trick question, as you coul dinsisat on measuring both with the same system.
Well, there is not enough data to answer this question... Are you weighting them in vacuum? Are you thinking of mass instead of weight (as many people do?) Do you include unmeasurable, but theoretically existent differences in gravity due to difference in size?
A troy ounce weighs 31.1 grams (the standard for measuring precious metals) An advp ounce (let's call it the supermarket ounce) weighs around 28.3 grams A troy pound is 12 troy ounces. A advp pound is of course 16 ounces. So....an ounce of gold weighs more than an ouce of cotton, but a pound of cotton weighs more than a "pound" of gold.
You are correct, sir. I posted this because there is some relevance for coin collectors who buy gold or silver bullion. Answers: 1. a. gold An ounce of gold weighs more, because gold is measured in troy ounces instead of the more common avoirdupois ounces. A troy ounce is equal to 480 grains (another unit of weight). An avoirdupois ounce weighs 437.5 grains. Therefore, a troy ounce of gold (480 grains) weighs more than an avoirdupois ounce of cotton (437.5 grains). 2. b. cotton A pound of cotton weighs more, because gold is measured in troy pounds and cotton is measured in avoirdupois pounds. A troy pound is equal to 12 troy ounces, or 12 x 480 grains = 5760 grains. An avoirdupois pound is equal to 16 avoirdupois ounces, or 16 x 437.5 grains = 7000 grains.
Notoco Please recheck your class schedule. This is the Numismatics class. The Physics class is down the hall. They do the pounds-force and pounds-mass down there. It would be fun to drag liquid ounces into this. "Does an ounce of water weigh more than an ounce of water ?" where the first ounce is liquid and the second ounce is avoirdupois.
I always understood gravity to be determined by only two things - mass and distance, such as in the following definition of gravity: "All matters attract all other matter with a force proportional to the product of their masses and inversely proportional to the square of the distance between them.” I believe that physical size, and presence or not of a vacuum have no effect upon gravitational forces, but I would be interested in reading about those theories if you can provide a link. Acceleration due to gravitational forces may be greatly affected by the presence of vs. lack of a vacuum, but the gravitational force itself is unchanged. I also believe that most people, at least in the U.S., think in units of weight (pounds), and not in units of mass (slugs). An object's mass is a constant, but it's weight will vary in proportion to changes in the acceleration of gravity for any specific locale. When considering an ounce (volume) of water, the temperature should also be given, as the density of water varies, in an unproportional fashion, with changes in temperature. The liquid water is most dense at 3.97 deg. Centrigrade, when it has a specific gravity of 1.0000. But, for a more commonly encountered temperature, 1 fluid ounce of water at 62 degrees (sp. gr. of 0.9832) will weigh 437.5 grains and have a volume of 1.732 cubic inches. The numbers will change if considering an Imperial ounce. A few interesting (at least to me) water facts: Water is the only substance on Earth that exists in all three physical states of matter: solid, liquid and gas. Water is the only substance where the maximum density does not occur when solidified. As ice is lighter than water, it floats. (Ring) Science class is over now, you may now return to your regularly scheduled numismatic thread.
Then an ounce (liquid) of water weighs the same as an ounce (avoirdupois) of water ! I guess that's where one of the two was defined with respect with the other. In the metric world, (MKS and CGS), many (if not all) of the units are linked together like that; I'm not used to seeing it with English units.
Yeah, sorry Bacchus, I just assumed a pound is a pound is a pound - that must be a leftover from the times I was thinking in meter/kilogram/second units...
Notoco, certainly no offense or abuse intended by quoting you in my post. Hope you did not perceive it as such, and my sincere apologies to you if you did take it that way. Hopefully such details will provide a bit of enlightenment to those so inclined. Lord knows my wife doesn't want to hear it.
"I believe that physical size, and presence or not of a vacuum have no effect upon gravitational forces" Don't forget Archimedes' Principle...
Archimedes Principle You’re correct, Archimedes Principle (AP) would have an effect on the weight a scale would measure if not measured in a vacuum. The pound of cotton would have greater volume than the pound of gold and thus would have more upward “pull” from the atmosphere than would gold. We don’t need to consider the same problem if the measurement was made underwater which has additional complexities (the cotton is absorbing water; the cotton, while solid, is not a solid block, so the water would “infiltrate” the outer volume of the cotton, etc.) which we might circumvent by stipulating the cotton is is contained in a vacuum-sealed virtually-weightless piece of shrinkwrap. This principle would not have any effect on the mass, and it would not have any effect on the gravitational pull on the gold or cotton, but I would think it would result in a force countering, the gravitational pull. I’m treating the gravitational force and the AP force as two different forces, the difference of which is the measured weight. For those not familiar with AP, think of a helium balloon. The balloon plastic and the contained helium have a certain combined weight. The air that the balloon displaces (the volume of the balloon) also has a certain weight. The balloon rises because the displaced air weight is greater than the combined weight of the plastic and helium, so the net weight is “negative”. Same thing with air bubbles rising in water. If the weight of the air was heavier than an equal volume of water, the bubbles would sink. I’m not a physicist, so if I have any of this wrong please correct me. Air at one atmosphere of pressure and 20 degrees C only weighs 1.204 mg per cubic centimeter, so I doubt if that is going to change the result of my original question. If I knew the density of cotton we could calculate the volume of a pound of cotton and multiply that by the density of air to determine the AP force and know for sure.
Which weighs more, a ton of helium filled balloons on the Earth or a ton of helium filled balloons on the moon. There are huge numbers of factors which affect our measurement of weight so defining all the conditions would be necessary to answer the question. Certainly there would be little difference if both objects were weighed in the same place and at the same time in a vacuum.
