It’s odd: Questions about the physical weight of data get asked fairly often — I don’t know what’s prompting it. Perhaps the move to SSDs?
The most recent iteration phrased it this way:
“Does data have physical weight? If something is 10 gigabytes, does it actually weigh whatever system you have it installed on down?”
My previous, less complete answer appears here; but since the question comes up repeatedly (and has generated some fun “angels-on-the-head-of-a-pin”-type arguments), I’ll update and add more detail here:
For electronic storage (RAM, SSDs, flash memory, etc.), yes, adding data directly increases its weight.
For traditional magnetic HDDs, also yes(!), but indirectly. An actively in-use HDD will weigh more than an inert HDD, but due to side effects of adding the data — not from the data itself.
It’s all small-scale physics, way below the level of human senses.
In electronic storage: Adding information to RAM, SSDs, flash memory, etc. — that is, storing a 1, instead of a 0 — requires storing an electric charge. Each electron has a very small weight (something like 9.10938215 × 10−31 kg), so adding electrons does mean adding a tiny amount of weight.
How much weight? To get a real-world answer, you have to make assumptions about how many electrons constitute a useful charge-state for whatever device you’re talking about, but one calculation says that 1GB of flash memory completely filled with 1s weighs something like 729 femtograms more than the same memory filled with zeros.
A femtogram is tinier than tiny: 0.000000000000001 kg.
(Want the math? See How much does a gigabyte worth of data physically weigh on a hard disk?)
So, yes: Electronic memory filled with ones will weigh a ridiculously small amount more than memory filled with zeros.
In magnetic storage: Hard drives (HDDs) work by flipping magnetic domains from North to South and back again. That, in and of itself, doesn’t change the weight of the drive, and that’s what my previous answer stated.
However, as was pointed out to me (in the very best angels-on-the-head-of-a-pin tradition), writing data to an HDD inevitably produces some waste heat in the magnetic domains being written — adding heat energy that wouldn’t be there if no data were being written. Very strictly speaking, heating anything increases its mass because energy and mass are equivalent (yup: E=mc2). So, very, very strictly speaking (look at those Angels dance!), an actively-writing HDD has a teeny-tiny bit of extra mass compared to the same HDD when it’s not writing. It’s an even smaller effect than trying to weigh electrons — already a ludicrously small amount! But if you’re a stickler (or are a fan of angelic footwork), then yes, the effect is there. 🙂
So: Yes, drives really do weigh more when in use.
But don’t worry. You won’t notice the extra weight.
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You are incorrect. The transistors used to store the data use a charge to store 0 and take that charge away to store 1. So they get lighter, not heavier!
https://www.sciencefocus.com/future-technology/does-a-usb-drive-get-heavier-as-you-store-more-files-on-it/
Second mistake, you state that hard drives (HHD’s) weigh more due to heat transfer while writing to them summarizing with “So: Yes, drives really do weigh more when in use.”
In use is not the same as stored data. You could be erasing data while using the drive, it would still heat up and weigh more while erasing the data! Also, the heat will radiate out of the drive while not in use which would make the stored data weigh the same as the erased data when the drive is cold. Therefore, in answer to the questions about stored data you have to say the drive weighs the same with or without data.