# What is the volume of a bit?

The whole internet (includint this post) weights the same as a strawberry. Ok, sounds good to me! I was wondering now what would be the volume (cubic ******) of… one bit.

A bit must have some sort of physical representation. Even if you represent the idea of a bit as a “yes” or “no” in your mind, your brain has some number of neurons dedicated to this, which is still a physical representation.

Since it’s now possible for physicists to position atoms one-by-one, I’ll argue that the smallest possible size of a bit is, at present, the size of an atom; an 8-bit byte could conceivably be represented by some combination of atoms and spaces (summing to 8) positioned in a line on a smooth substrate.

If you’re looking for a more convenient, easily adjustable bit, you’ll need some configuration of transistors, as on a computer chip. Researchers are now making transistors a few atoms wide (no more than a nanometer total), so we’re still able to make physical representations of bits that are pretty small. I don’t know how fast those nano-scale bits are.

If you’re looking for a convenient and relatively fast-changing bit, you need something like what’s currently in a mass-produced computer chip, and now we’re talking about something that’s on the order of many nanometers in size.

So… I could divide the writeable area of a hard drive by the amount of data it can store and get the approximate area of a bit?

http://en.wikipedia.org/wiki/Memory_storage_density

That article says

That’s absurd! Does the light switch on your wall weigh more, depending on if it is in the up or down position? The bits in your Kindle are EXACTLY the same.

If the article is right, then the non-volatile memory in a Kindle has more potential energy in one state than in the other state. With E=MC[sup]2[/sup], then yes, one state of memory could indeed weigh more than another.

The space shuttle had the same issue: the hydrogen and oxygen used by the main engines during a launch weighs 2 grams more than the resulting water.

How about mass? I have a 30+ year-old answer for that. When I was sort of a techno-geek ca 1980 a charge of about 100,000 electrons was used to store a bit on MOSFET storage chips. That works out to about 9 zeptograms, if my arithmetic is correct. … Or maybe holes were used instead of electrons; that would be negative 9 zeptograms. :smack:

I think widths were about 1 micrometer when I was a techno-geek. Some thought that would be the end of it. I worked with the guy who had patents on the FET storage cell. “You can detect one electron if you’re smart enough” was his answer (in a thick Eastern European accent) when I asked him about it. (I’ll admit my ego was stoked when he called me the best circuit designer he’d ever met. He was certainly the best I’d ever met.)