The thicker a wire, the lower the resistance it has. This may be somewhat counterintuitive. You might imagine that a thick wire requires much more electricity to “fill it up.” But actually the thickness of the wire makes available many more electrons to move through the wire.
Current is related to the number of electrons actually zipping around the circuit. Current is measured in amperes, named after André Marie Ampère (1775–1836), but everybody calls them amps, as in “a 10-amp fuse.” To get one amp of current, you need 6,240,000,000,000,000,000 electrons flowing past a particular point per second.
The key word here is two. Two types of blinks, two vowel sounds, two different anything, really, can with suitable combinations convey all types of information.
The earth is to electrons as an ocean is to drops of water. The earth is a virtually limitless source of electrons and also a giant sink for electrons.
Voltage refers to a potential for doing work. Voltage exists whether or not something is hooked up to a battery.
During storms, the bottoms of clouds accumulate electrons while the tops of clouds lose electrons; eventually, the imbalance is evened out with a stroke of lightning. Lightning is a lot of electrons moving very quickly from one spot to another.
In this book, the word code usually means a system for transferring information among people and machines. In other words, a code lets you communicate. Sometimes we think of codes as secret. But most codes are not. Indeed, most codes must be well understood because they’re the basis of human communication.
Morse code is said to be a binary (literally meaning two by two) code because the components of the code consist of only two things—a dot and a dash.
What might have helped Babbage, we know now, was the realization that perhaps instead of gears and levers to perform calculations, a computer might better be built out of telegraph relays. Yes, telegraph relays.
In the computer age, the bit has come to be regarded as the basic building block of information.