Chronology Current Month Current Thread Current Date
[Year List] [Month List (current year)] [Date Index] [Thread Index] [Thread Prev] [Thread Next] [Date Prev] [Date Next]

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.