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Re: [Phys-L] playing for keeps

True, but I still hate counting out on my fingers to get to the right number. Any hints for that? Since I don't read resistors very often, I no longer can do it without running through the whole mnemonic, or equivalently,

Black Brown -RAINBOW- Gray White

Black Brown -ROYGBV- Gray White

(I too gave up using "indigo" long ago. Hey, it's just deep blue!)

KC

-----Original Message-----
From: Phys-l [mailto:phys-l-bounces@phys-l.org] On Behalf Of LaMontagne, Bob
Sent: Saturday, 29 June 2013 4:27 PM
To: Phys-L@Phys-L.org
Subject: Re: [Phys-L] playing for keeps

What about the mnemonic for the color coding of resistance. Once learned, I don't think it is possible to forget it - unless you have been forced to memorize one of the more politically correct versions.

:-)

Bob at PC
________________________________________
From: Phys-l [phys-l-bounces@phys-l.org] on behalf of John Clement [clement@hal-pc.org]
Sent: Saturday, June 29, 2013 1:52 PM
To: Phys-L@Phys-L.org
Subject: Re: [Phys-L] playing for keeps

Rubbish. Schools spend a huge time on mnemonics, and as a result students never get to deeper levels. They just memorize the mnemonic rules how about "Leo says gr" in chemistry or "An ideal vacation is a hot place with low pressure from your parents" to know when gasses depart from ideal conditions. These are routinely substituted for reasoning in Regents exam classes. The problem with this type of thing is that students forget what they stand for, or get them backwards. If you understand that ideal means you have treated the gas as point particles, then when they are close or they change phase the size of the molecule intrudes into the situation. You don't need the mnemonic. The mnemonic essentially kills understanding by promoting memorization over reasoning.

Mnemonics are useful for things which are arbitrary. It can be useful for the resistor code, but this example is not the best because the code has been arranged according to the rainbow and brightness. In physics mnemonics are the kiss of death because they are substituted for thinking. If you want long term retention, then deep understanding is the key. That is why FCI results are constant up to 3 years from the course. Understanding does not fade, when random facts fade, distort, and reverse.

Look at how math is taught as rote procedures. Students then see 5X=8 and come up with answer X=3. They know you either divide or subtract, but without understanding proportional reasoning they get the rule backwards. I have seen them use the "King Henry dances" mnemonic (which I do not remember
well) and convert 3cm into 300m. Again they have the mnemonic and they know they move the decimal point, but they forget the direction. But if you have a mental picture of this conversion you never get it wrong.

And one set of mnemonics does not make sense. Why memorize the spaces and lines on the staff separately. They are arranged in alphabetical order and all you need to know is one line or space, then the rest are in order. The other fact is that notes repeat after f. When you use it enough, the association eventually becomes automatic.

Incidentally being slightly dyslexic I have difficulty with mnemonics and so had to rely on understanding. Mnemonics and other tricks are useful if you use them frequently and need to remember things quickly. Also they are dependent on how the individual learns.

A friend is fantastic at remembering facts. She tried to tell me a system which works for everyone. You can remember a name by having a picture for each letter and arrange the pictures in the order of the letters, then just bring up the picture. But what if you can't bring up the picture???? What if you have difficulty remembering which picture goes with which letter?
Those who have this ability have a gift that they can use, but this gift does not confer the ability to reason, and physics is all about reasoning, not memorization. Indeed I suspect that people with eidetic memories mostly do not go into science because they have not developed reasoning because memorization is so easy for them. But good memories are very useful for politics or business where it helps you appear to be friendly because you know all the names. In science a good memory is not the key, but rather good understanding and knowing where to look up what you need is more important.

Mnemonics should be banned in school! I remember only one "Roy GBU(V)" for the rainbow, but I do not need it. Incidentally they used to teach in NY the rainbow without indigo which is not an obviously different color, merely a shade of another color. But other states have mandated the 7 color rainbow. This is purely a memorized fact that should not be tested, and makes no sense for people with color blindness. It doesn't exist as a fact for them. I wonder if standard film or color monitors even reproduce colors well enough to make indigo evident.

Since we are on the subject of color, it turns out that you can only distinguish about 6 colors for isolated lines. If you are trying to correct the color of a picture, using a computer drawing program, it turns out to be a very difficult process. You can select a color from one region, that looks right, but when isolated does not. Then sometimes, but often not, it still works when painted where you want to correct color. This just points up how the textbook and artist descriptions of the color wheel are inaccurate. We really do not percieve absolute color, but rather colors relative to adjacent colors. Visual color and brightness are extremly relative and context dependent. Why do the physics texts have to ignore color constancy?

John M. Clement
Houston, TX


My point is simple: If you decide that long-term retention is one of
the essential goals, then it dramatically changes how you go about
teaching. For starters, you find yourself spending a huge amount of
time and effort on mnemonics. It doesn't matter how true or important
or elegant something is, if it will not be remembered.

The textbooks are, by and large, terrible at this. A good teacher can
help a lot, by passing on the mnemonics, the lore, the rules of thumb,
et cetera. However, it doesn't have to be that way. There's no
reason why the textbooks couldn't include a ton of mnemonics.



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Forum for Physics Educators
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http://www.phys-l.org/mailman/listinfo/phys-l