Motivation
People frequently use the word "digital" to describe anything that's modern. It means something specific, and it's pretty easy to learn. And learning is cooool.
"Digital"
In modern society, "digital" is often used in non-scientific ways from "digital music" to vague sentiments like "the Digital Age." Digital and analog have simple meanings, and neither has anything to do with computers. Digital simply means you're using a set of values that you know the exact values of. In computers, that set of values is 0 and 1. It is a discrete set of values."Analog"
Analog simply means you're using the full, continuous range all values between your minimum and maximum. There are an infinite number of values between 0 and 1. For example, 0.5 and 0.6. But I can "go between" these numbers with the value 0.55. and I can "go between" 0.55 and 0.6 with 0.575. I can keep doing this infinitely. Analog systems do not measure, track or store discrete values.Examples
The simplest example of this I can think of involves musical instruments.Imagine a trombone: you can play an E by holding the slide in a certain position. To play an F, you move the slide a little closer in, but if you move it a little less than you should, you're between the two notes. Since you're not playing an E or an F, it's probably going to sound bad because you'll be flat. You can play an E and an F, but you can also play the full, infinite range of pitches between those 2 notes.
On piano however, you press the E key, you get an E, you press the F, you get an F. You cannot play the pitches between those notes. That's nice because it's one less thing to worry about... but you also can't play the "womp womp" sound.
The trombone is analog and the piano is digital.
A few more quick examples are a full-on rainbow, versus a simple rainbow:
And slider belt versus a belt with holes:
I used them some in the 80s and was surprised how well they worked. I'm guessing the error rates on these tapes wasn't too bad because with binary data, only having 2 values to represent meant you could make it pretty clear which was which. It wasn't like playing an E versus an F on a piano (most humans couldn't tell you which was which) it was probably more like playing the very lowest note on a piano versus the very highest (most humans could easily tell you which was which).
If you made copies with a low quality tape recorder vs a higher quality one, it made a difference. It might even make a difference if you made the copy in a room that was really hot or humid. This is because the data on the tape was analog, and the tape recorder reading that tape is not precise enough to read the data exactly. In the same way, while the best trombone player in the world is very very close to hitting that E on their instrument, their finger placement will probably actually be sharp or flat by at least a nanometer or two...
However, if you make a copy of a music CD, you can make a copy of that copy, and a copy of that copy, etc. and it will be an exact copy of the original. The original and all of the copies are perfectly identical. The modern analogy would of course be just emailing the picture to your friend so that they have a copy.
A few more quick examples are a full-on rainbow, versus a simple rainbow:
And slider belt versus a belt with holes:
The Physical Medium vs How It's Used
In the case of the belts above, you might notice something: The "digital" belt with the holes cannot be used in an "analog" way. The "analog" belt however... if you used white paint to make lines on it every inch or so, and you chose to only use the belt at those increments, you would effectively be using the "analog" slider belt in a "digital" way. In fact this is true of cassette tapes (think 1980s). Cassette tapes were primarily used to store music, for example MC Hammer's "Too Legit to Quit," but they were also used in computer systems (Atari, Commodore, etc.) to store binary (digital) data.I used them some in the 80s and was surprised how well they worked. I'm guessing the error rates on these tapes wasn't too bad because with binary data, only having 2 values to represent meant you could make it pretty clear which was which. It wasn't like playing an E versus an F on a piano (most humans couldn't tell you which was which) it was probably more like playing the very lowest note on a piano versus the very highest (most humans could easily tell you which was which).
Digital as "Better"
The reason people think of digital as better than analog is because you can make a perfect copy of it. A cassette tape with music on it is analog. If you recall, every time you made a copy of one, the quality deteriorated a little. If you made a copy of your friend's tape, then another friend made a copy of your copy, it sounded noticeably worse than the original. An analogy for modern times might be if you take a picture with your phone, and then someone takes a picture of your phone's screen, and then someone else takes a picture of their phone's screen. That 3rd picture's not going to look too good.If you made copies with a low quality tape recorder vs a higher quality one, it made a difference. It might even make a difference if you made the copy in a room that was really hot or humid. This is because the data on the tape was analog, and the tape recorder reading that tape is not precise enough to read the data exactly. In the same way, while the best trombone player in the world is very very close to hitting that E on their instrument, their finger placement will probably actually be sharp or flat by at least a nanometer or two...
However, if you make a copy of a music CD, you can make a copy of that copy, and a copy of that copy, etc. and it will be an exact copy of the original. The original and all of the copies are perfectly identical. The modern analogy would of course be just emailing the picture to your friend so that they have a copy.
