## Monday, March 29, 2010

### Analog, or can you lend me a hand?

The last blog posting subject was the word DIGITAL. Today's is ANALOG (or analogue).

Analog is derived from the term analogous which means proportionate, or similar - in other words, something that is similar enough to another thing that we can use it to make a comparison.

Why is this math? We start teaching analog in the First Grade when we describe a clock that has hands to point out the time. Most do not have hands in the sense that this Mickey Mouse watch has hands, but they are similar to arms and hands. We call this an analog clock to distinguish it from a digital clock which has digits to indicate the time (and no hands).

Here are a few sample analog clocks and watches. We provide an analogous grouping in First Grade.

We often use the word analog to refer to things that are done in the old way rather than the new digital way. For example, a pencil might be analog and a computer keyboard digital. This is a messy way to use the words, but most people would probably understand what we mean. Shall we compare a few items?

 DIGITAL ANALOG keyboard pencil solid state vacuum tubes (valves) switch rotary knob touch-tone rotary dial numerals hands digits moving needle on/off variable CD and DVD vinyl records looking through a window screen looking through an open window

Here's a way to combine analog and digital to display the time:

Some clever Swedish software guys figured this out. You need an array of 6 externally-controlled analog clocks for each digit. And it takes some fancy thinking to work out the controls!

How many clocks are needed to show 24 hours, minutes and seconds?
Do any of those analog clocks need to have 3 hands?