## Sunday, April 03, 2016

### 1.1 Electricity and the Electron

1. In 1980, when I started my freshman year in high school, I signed up for an elective I think was called "Electronics 1." It was with Mr. Richard Brandt, a delightful if shall we say slightly overweight teacher. It was a different sort of class.

I suspect most of the students were on a vocational track. It was geared around the kinds of things you would need to know to be an electrician. In my third year I built a power supply and circuit board that I still have. Radio Shack has long stopped selling the kinds of transistors, resistors, diodes, and capacitors of that day, which was right on the cusp of integrated circuits.

I needed three slots in my circuit board for one Radio Shack transistor in 1983. Now an iPhone 8 has 2 billion of them on a chip. Sigh.

So we worked at our own pace through a series of self-directed Navy Basic Electricity and Electronic books (you can now download them for free). The books were from 1972 (or earlier) and were initially designed for electricians in the Navy. For example, some of the first module talks about the kinds of batteries they used to have on submarines.

My old friend Casey Walker and I made a number of visits to the public school Book Depository our senior year and snatched a host of the textbooks we'd had in high school. I think that's where I nabbed all the Navy modules I'd gone through in two and a half years with Mr. Brandt.

In my plot to take over the universe, I've been reviewing a lesson each weekend and thought I'd blog down study notes for future review. These books are so tedious. The questions are painfully simple but it asks you the same questions over and over and over in slightly different ways. It's learning... and death... by repetition.

2. So Module 1 (i.e., book 1) is called "Electrical Current," and Lesson 1 is about "Electricity and the Electron." Here's the scoop:
• Electricity does work.
• All matter is made up of atoms. Atoms are very, very small. They are so small that they are the stuff of theory rather than direct observation (although now see this).
• At the center of an atom is a clump of small "particles." The clump in the center is called the nucleus, and the particles are called protons and neutrons.
• Most of the space around the nucleus is empty. The third basic "particle" in an atom is about 100,000 nucleus lengths away. It's called an electron.
• Electrons thus surround the nucleus. You might start by thinking of planets surrounding the sun, although that's not quite right. Electrons are much, much smaller than protons (about 1/1845 as massive)
• So atoms are made up of protons, neutrons, and electrons.
• Electricity is the movement of electrons through a medium.
• Wires are solid. They don't have holes in the middle for the electrons. :-)
• Different kinds of atoms have different numbers of protons. (For example, copper has 29 protons in its nucleus. Most copper atoms have 34 neutrons in their nucleus. And in its neutral state, copper has 29 electrons.)
Next week: 1.2 Electron movement.