Official: Kindles get heavier as you add e-books Download an e-book and your reader gets (microscopically) heavier. So says University of California at Berkeley boffin John Kubiatowicz in the pages of the New York Times. His argument: that energy is bound in the process of storing the book's bits in the reader's Flash memory and, according to Einstein's most famous equation …
If you download something then it takes power to do so so the battery will lose more mass than anything added by a book. In fact, thinking harder, it will be the battery supplying the mass for the book so ideally there would be no net change.
Plus. Time Slows so 'longer to read' and Length Contracts so 'thicker'.
But SURELY, as you're in the same reference frame as your ebook, then it only seems thicker and heavier to the chap watching you from the platform.
Taking this too seriously, you say? This is not the Daily Mail, Tony, this is the Register - a veritable hive of pedants, scientists and SF afficianados. You asked for it, my dear chap....
Does this article hold water?
It's beren a long time since my degree, but it seems to me that the kindle maintains the memory state irrespective of whether there are books stored within it. Although one could imagine a computer memory using a scheme such as run-length encoding, or at least switching off entire chips when they are all zero, this is not how it works. The entropy of empty memory is the same as that of full memory under most designs.
Furthermore, flash does not use energy to maintain state, so there is no energy difference between a zero and and one. Is there?
This might be correct if the device works in the simplistic manner which he assumes, i.e. "Assuming that all these bits in an empty four-gigabyte Kindle are in a lower energy state and that half have a higher energy in a full Kindle". Is that probable? I don't think so.
The device must have been tested or formatted before it left the factory. If it was tested with repeated cycles of "10101010" then "01010101" to find any bad 'bits' abd this, which pattern was left in the memory (just marking the space as 'empty' in the file system), then 50% of the bits would be full when it left the factory.
Depending on your language and choice of reading matter, adding e-books might actually reduce the number of bits that contain the higher energy electrons, thus reducing the mass of the device.
Must try harder, see me after class.
As the memory is in flash, the actual data will be an exces or deficit of electrons.
Guessing that the flash starts off as zeros and has the ones programmed in by adding electrons, then any content will weigh more than no content.
Alternatively, if the flash starts off as ones and has zeros set by the programming then the book will get lighter with new content
Obviously YMMV
Theis is NAND flash. The flash starts as ones, but gets programmed to zero. Programming cells is done by injecting positive charge into a floating gate (ie. electrons are removed).
Each bit takes somewhere around 100 electrons to program. Assuming 50% of bits are programmed, that's an average of 50 electrons or 400 per byte.
An electron has a mass of approx 10^-30kg. That makes each byte 4x10^-28kg, each GByte around 4x10^-19kg
So the moral of the story is to download more and make it easier to move around.
If you read your kindle outside of a clean room then it will gain even more weight from dust landing on it. Actually thinking about it there are quite a lot of things that can make a kindle gain weight - I advise against taking your kindle anywhere that you don't have ready access to heavy lifting equipment just in case it gets too heavy for you to carry yourself.
This would never happen with an iProduct, anyone claiming differently is probably holding it wrong.
'Empty' flash memory is sert to all '1'.
Erasing a flash cell sets it to logic high...
So writing means only zeroes get written....
Thus : storing more books creates additional zeroes : tablet becomes lighter ...
a factory fresh device will be heavier than a used one.
Food for thought : deleting something only erases the index pointer... the data is still there until overwritten.
"The best thing to do, then, is not read your Kindle on the train, as the conveyance's velocity will only make it even heavier. And thicker."
...but wouldn't the Lorentz contraction make your Kindle appear THINNER on the train...? (Assuming, of course, that the Kindle is held vertically with the height and width perpendicular to the direction of motion.)
The only way that it would appear THICKER would be if it was held with one of the LONGER axes pointing in the direction of travel, and even then the thickness would only APPEAR greater in proportion to the contraction of the affected axis, it wouldn't actually GET thicker.
That's the way that I remember it, at least.
This article really hasn't considered all the implications of E=mc².
The dominant effects will be those representing the largest energy changes in the Kindle and from an electrical point of view this is clearly going to be the issue of battery charge so as you read the Kindle gets lighter.
The next largest effect is likely to be the Kindle cooling off once taken out of your pocket. As it cools it loses energy and hence mass. Mind you this raises the question of what is meant by "heavier" as the reduced bouyancy due to the thermal contraction may actually be more significant. Once you start down the cheesepairing route there are an awful lot of remarkably small numbers to take into account.
There are a lot more things like this that need to be considered before the internal energy state of the flash memory becomes a significant factor.
And ... if you thought measuring the speed of neutrinos is difficult ...
This idea surfaced (!) a couple of years ago for hard disks. There, IMHO, the refutation is easier: a magnetic domain weighs the same no matter what way up it is.
Now I know less about the structure of eeprom cells, and it is not impossible that there are more minority carriers trapped in a '1' than a '0'. Are they symmetrical, these days, or a single junction? That might represent a difference in mass: but as others have said the battery would have to be topped back up before making any measurements.
That equation does not mean that mass increases when there's more energy! It means that the energy in a thing is equal to its mass times c squared. It's one or the other, not both. Energising a flash ram does not increase the mass. The electrons don't get more mass, they just get more energetic (more speed, higher orbit, etc). When I climb some stairs my mass doesn't go up, even though I've gained a whole lot of energy. What do they teach the kids these days!
Thank you for posting that - if said "boffin" did actually use the E=mc^2 to suggest an increase in weight for all those higher-energy electrons and wasn't just taking the piss himself, el Reg (and the many other news outlets who presumably don't have anyone at all with a teensy bit of science to point out the fail) should simply have pointed and laughed.
Surely every time you perform a data-altering on the flash drive (write / delete) you are using energy to change the data! So, over time and use the device will continue to absorb energy and mass.
I predict in 100 years these devices will have absorbed so much energy the world will be covered in tiny black holes originating from many flash devices!
A Kindle with no books loaded contains an equal number of electrons as it does protons (excluding any static charge), and a kindle stuffed with books contains the same balance. Is this boffin seriously suggesting that new atoms are added to the flash memory by writing data? Or that the existing atoms gain protons (and so change to become different elements)? Surely the electrons simply move from one part of the flash cell memory to another when a value is written.
So does a stretched rubber band weigh more than an unstretched one?
Potential energy /= mass, I thought. A bucket of water at the top of a mountain is the same mass as at the bottom, but has potential energy, right?
BUT a stretched rubber band is storing energy in Van Der Waals forces & latent heat, so E=mc^2 yes, that increases the mass, right? just by not a measurable amount.
So... a battery - they are like a rubber band, potential energy using a chemical-electric energy gradient. Electrons really want to get from - to +, but the overall number of electrons doesn't change. ie. the Battery (or cell) DOESN'T have an overall 'charge' in the classical physics sense. Am I right?
Ok, um, I choose NO - the Kindle does not weigh more, as that would imply direct mass -> energy -> mass conversion, and stuff like that ALWAYS kicks out a few alphas, betas, gammas and probably a plethora of neutrinos.
is heavier than an unwound one, a charged battery is heavier than a discharged one etc. It's all unmeasurably small.
The premise of the original article does seem wrong though (I know about entropy, but does it really store more energy having Flash bits ordered in the form of "Ulysses" than in a random pattern of ones and zeroes, which would look much the same to an alien lifeform?). And it's all outweighed by the material you just rubbed off the page-turning keys by using the Kindle. Look how polished the space bar is on a well-used keyboard.
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