Why is shredded paper lighter than unshredded paper?

Question

We recycle paper at my work by shreddin everythin.

Lets say I have 10Kilo's of paper to shred- once its shredded, it's as light as anything, but the same amount of paper! Why is this?

Best answer will be chosen! lol

Thanks so far- I know it's easier to carry. But i'm totally convinced that if I were to but a bag of shredded paper on the scales it would be a lot lighter than the unshredded same amount

Answer 1

Actually, a bag of shreddings is _heavier_ than a bag with the same amount of paper. Why?

In shredded paper is dense, packed together.

When you shred it, it takes more space, (unless you compact the shreddings afterwards) whilst keeping the same mass. Same mass in a larger area always seems lighter but it's actually the same exact weight.

Now... I did say it was heavier. This is because when you decreased the density by shredding the paper, you did so by producing lots of air pockets in between the shreddings.

Weigh an empty balloon against a balloon filled with air and see if you notice a slight difference. You get the best effect if you use a balance scale. [The full balloon weighs more than the empty balloon because air has weight.]

Answer 2

A lot of physics is counter-intuitive. You say you're sure that if you weighed the paper, the shredded paper would be lighter-- the only way you can possibly demonstrate that they are the same weight (or prove your theory that they'll be different weights) is to actually shred some paper, and weigh it and unshredded paper.

From what others are saying about density and perception, you might also be interested in trying this experiment: Take the same amount of paper, and crumple up each individual sheet into a big, loose ball and put them in a bag. Does this bag seem to weigh less or more than the bag of shredded paper? The bag with a ream of intact paper? You might want another bag of loose sheets of paper.

Remember that for centuries, people thought that lighter things fell slower than heavier things. It took actually SEEING a heavy and light object fall together at the same speed to convince them otherwise. You obviously haven't taken physics class, because if you had, you would know from experience (the demos in class) that physics does things so surprising and counterintuitive that it seems like magic. You should see demos on centripetal motion; transferrence of rotation; and impulse. It's like the Twilight Zone!

Answer 3

Hello,

Answer, Are you really sure the same weight of paper shredded isnt the same weight you end up with??

**The paper will loose some weight via the shredding process as bits are lost when it goes through the teeth of the shredder. But I would suggest that 10Kilos of paper will end up only farctionally less than 10kilos. OK the shape or volume of the paper has changed but the weight wont change much I suspect, its only a perception of weight change its NOT an actual weight change in the real sense.

If you dont believe me you can test this by weighting the paper before and after shredding. There will be little or no change in my opinion.

IR

Answer 4

I think the main reason more companies don't recycle it is because they don't feel there is money to be made in recycling shredded paper. It is unfortunate because in the long run there is a higher cost to buying new paper and causing more trees to have to be cut down. I would say if you are going to burn it and not recycle it then use the paper to help start your grill if you use charcoal or to start a fire in the fireplace or when camping. If you use it to start your charcoal in a grill then you don't have to use lighter fluid and your food will taste a lot better. By the way thank you to the previous poster who gave instructions on how to recycle the shredded paper. I will put them to good use once I have an apartment of my own.

Answer 5

With my superior physics knowledge (i.e. not much) i will enlighten you.

Its not lighter, its a bit like the tonne of feathers or a tonne of bricks saying. The only explanation i can give is this.

Im guessing you put the shredded paper into a black bag or something similar) after shredding. The weight to mass ratio changes. It takes up more area but is riddles with spaces. The mass is spread more evenly and easyer to move. Overall it still weights the same. Not scientific and someone will do better im sure. Its also 9:55am and iv stayed up all night so brains gone weird and wired with coffeeee. Maaaaaaaa!!!!!!

Answer 6

Considering that weight = mass*gravity:

If you have 10kg of paper and after shredding it you still have the same amount of paper, either the force of gravity (9.8m/s) has changed or you are accelerating in a vertical direction while weighing the paper.
Volume doesn't factor when determining weight (unless using d=mv). In the end you still have 10kg of paper.
Put it to the scale and if it is different, empty the shavings out of the shredder. Then if it truly is different, call Ripley's!!!

Answer 7

The 10Kilo's weight of the paper is equal to the total weight of the atoms and molecules making up the paper. If the shredding process does not add or subtract atoms or molecules the weight of the paper will not change. The total is equal to the sum of its parts.

Answer 8

There cannot be any change in mass... CHanging mass into something else... is really explosive! Try E= mc^2...
About this debate about density changing? yes, it now occupies a larger volume, so it gives the perception it is 'lighter'. Even then, the difference is too small to be noticable.
Back in the army, I used to clear the shredded paper from my office on a daily basis... trust me, it is equally heavy n exhausting.

Answer 9

I think it has more to do with perception than physics.
10kg of flat sheet paper is quite dense, probably occupying no more than 2 cubic feet. You'd expect something this small to be quite light, you try lifting it with one hand but it's not light, it weighs 10kg, it seems heavy.

The same mass of shredded paper probably occupies about ten times this volume. From a perception standpoint, you'd expect it to weigh ten times as much. You need to use both hands to carry a big box full of shreded paper, but it only weighs 10kg (plus a bit for the box and the air), you can easily carry 10kg with both hands so it seems light.

Cheers.

Answer 10

Isn't it something to do with the amount of air mixed in with the shredded paper?