One pound coffee beans = one pound ground?

[Smeghead]

If there IS a loss of weight, then by the conservation of mass, it must have gone somewhere…VOILA! You’ve discovered cold fusion! Power your house by grinding coffee!

[Telemark]

@Smeghead

Power your house by grinding coffee!

Hell, I know people who power their lives that way.

[UncleBeer]

If there IS a loss of weight, then by the conservation of mass, it must have gone somewhere…VOILA! You’ve discovered cold fusion!

Ugh. Cold coffee. Bleah.

[Cheez_Whia]

@CookingWithGas

What’s your definition of a ton? Equal mass of brick and feathers might show the feathers lighter on a scale due to bouyancy effects in the air at sea level. If by a ton, you mean “when placed on a scale, reads 1 ton” and if by “weighs” you mean “the value shown when placed on a scale”, then they’re the same by definition.

As to the OP, the act of grinding the beans per se does not change the weight. However, things like adding heat during the grinding process could increase the mass (if you’re a relativist). But loss of grounds in the machine and loss of molecules in the air due to increased surface area are not direct results of the grinding but after-effects.

1 Ton=2000 lbs. avoirdupois. As opposed to a long ton or metric ton. Getting a little too serious with what was obviously meant as a joke, hmm? Hint: this is also a joke. Just so you know.

[Contrapuntal]

@Shalmanese

Packing efficiency is independant of size of uniformly sized object but packing efficiency increases proportionally to the variability of size. You can pack rocks and sand more efficiently than just rocks.

Coffee beans are very uniform in size whereas presumably the grounds are less uniform, leading to more efficient packing. Also, packing theory only applies to rigid objects. I’m willing to be that grounds are significantly less rigid than beans, further increasing density.

I’m lost here.
Which is more easily packed into a cubical box with a volume of 100 square centimetres?

1. 100 cubes exactly one square centimetre in volume.
2. 100 spheres exactly one square centimetre in volume.
3. 100 randomly shaped objects exactly one centimetre in volume.

I think the grounds pack tighter than the beans because there is less airspace between one, not because of their shape.

[Danalan]

@singular1

Okay, this is probably a really stupid question, but lacking a scale, one I can’t check myself. If you take one pound of coffee beans and grind it up, do you wind up with one pound of grounds, or does the molecular change of the bean result in a weight difference? It sure feels lighter…

To answer the OP, yes, this is a stupid question. It’s not really stupid, just average stupid. The physical act of grinding does not change the weight of the coffee beans. The difference you are sensing is an illusion, a trick of the mind. Your brain is telling you that the grounds must be lighter, because they are smaller. Perception is not always reality.

[Contrapuntal]

That should be between each one.

[spifflog]

@Danalan

To answer the OP, yes, this is a stupid question. It’s not really stupid, just average stupid. The physical act of grinding does not change the weight of the coffee beans. The difference you are sensing is an illusion, a trick of the mind. Your brain is telling you that the grounds must be lighter, because they are smaller. Perception is not always reality.

No, it’s a really stupid question.

[Shalmanese]

@Contrapuntal

I’m lost here.
Which is more easily packed into a cubical box with a volume of 100 square centimetres?

1. 100 cubes exactly one square centimetre in volume.
2. 100 spheres exactly one square centimetre in volume.
3. 100 randomly shaped objects exactly one centimetre in volume.

I think the grounds pack tighter than the beans because there is less airspace between one, not because of their shape.

The original theory only applies to spheres although I don’t know if it’s been extended to anything else.

But, rather counterintuitively, 100 1cm^3 spheres will fit into the exact same volume as 1000 0.1cm^3 spheres and 10,000 0.01cm^3 spheres. This applies to both optimal packing, random packing and least-optimal packing IIRC.

[Contrapuntal]

@Shalmanese

The original theory only applies to spheres although I don’t know if it’s been extended to anything else.

But, rather counterintuitively, 100 1cm^3 spheres will fit into the exact same volume as 1000 0.1cm^3 spheres and 10,000 0.01cm^3 spheres. This applies to both optimal packing, random packing and least-optimal packing IIRC.

What about two 50cm^3 spheres? Only one of those will fit completely inside a 100cm^3 cubical box.
Surely, packing cubes inside of cubes is the most efficient configuration, is it not?

[Chronos]

Packing efficiency is independant of size of uniformly sized object but packing efficiency increases proportionally to the variability of size. You can pack rocks and sand more efficiently than just rocks.

You can also pack rocks and sand more efficiently than just sand. I’m sure you knew that already, but many other folks don’t.

For any given shape, small objects will have smaller gaps than large objects, but the small objects will also have more gaps. Packing efficiency does, of course, depend on shape, and there are some shapes which will pack more efficiently than others. Some shapes, such as cubes (also many prisms, rhombic dodecahedra, and a few others), pack completely efficiently, with no gaps at all. All of this is neglecting edge effects: If the space you’re packing isn’t an exact multiple of the size of your cubes, then yes, there’s going to be some wasted space, but one can fix this by making the cubes larger or smaller.

With all that said, I’m not really sure how to model coffee grounds. It seems pretty safe to call coffee beans spheres (approximately, at least), but grounds would not be spherical, and while some shapes pack better than spheres, some are worse. I also don’t know how much variation there is in the size of coffee grounds. So I don’t have enough information to say how efficiently grounds would pack, so my default assumption (with large error bars) is that they pack about as efficiently as uniform spheres.