Naked Science Forum
On the Lighter Side => That CAN'T be true! => Topic started by: Morgan IAT on 07/02/2017 16:45:33
-
Is it true that an empty hard drive or memory card weighs less when it's new than after it's been filled with information?
-
The answer is most likely to be no. The storage of data on a memory stick, hard disc or SD card corresponds to setting "bits" into one position or another corresponding to a binary 1 or a 0; as such the "data" have no mass.
You can think of it like an abacus full of beads. The information is stored by sliding the beads to a different position on the abacus; overall the number of beads - and hence the weight of the abacus - has not changed, merely the configuration of the beads.
We've discussed this in various forms a couple of times over the years; here are some references to the earlier discussions:
Debate here on the forum: Does my ipod weigh more when it's full of music? (https://www.thenakedscientists.com/forum/index.php?topic=15896.0)
Discussion on the Naked Scientists Podcast: Will an iPod weigh more when it's filled with music? (https://www.thenakedscientists.com/articles/questions/will-ipod-weigh-more-when-its-full-music)
-
Maybe some old hard drive disks would weigh less after being used many times. A loss due to friction not really noticeable I guess.
-
Hard drives might lose mass due to outgassing of the volatile components of the actual materials used to make them, but this is going to happen wether or not data is stored on there, it is strictly a function of temperature, time and if the parts are spinning for the lubricants. The actual data itself will not change in mass much, easily a few orders of magnitude below the changes caused by adsorbtion of atmospheric water into the material that make it up, like the printed circuit boards, the epoxy packages and even the paint film. Even the aluminium casing will have changes in mass due to hydrogen from casting diffusing out of it. and for the newer helium filled drives this will also diffuse through the seemingly solid case in any case.
-
Maybe some old hard drive disks would weigh less after being used many times. A loss due to friction not really noticeable I guess.
I don't understand what you mean by "loss due to friction". Were you thinking more along the lines of @SeanB who is suggesting outgassing of lubricant over time?
-
Think he assumes the surface of the platter is being worn, but as the head both floats on the surface, and there is a filter to keep fine debris out ( and thus in) there will be no wear particles leaving the drive at all. No, there will be no frictional loss due to particles being worn off the platters by the heads, or on the head stops ( there to park them when the drive is in power off so they do not actually molecularly bond to the surface anyway) and leaving the drive, there is both a ultrafine particle filter, plus a long meandering pathway that they have to travel down, and this barely allows molecules of air through, plus it is hydrophobic to keep moisture out as well.
-
Is it true that an empty hard drive or memory card weighs less when it's new than after it's been filled with information?
No. Where did you hear that?
-
I think the question being asked does information have mass ?, as energy is used to store it I would think the answer is yes but you would be hard put to weigh it.
-
My flash-drive definitely loses mass ... when I crash it again the wall for not being recognized.