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SCREAM: But what about internal energy??? This is one of the most
important
places to put energy as far as most people are concerned. And of course
internal has 2 manifestations potential (where you stretch bonds) and
kinetic. I don't like acronyms because they try to classify things too
neatly. Rather than acronyms students need to think through whether there
might be energy associated with a particular process. Teaching it as a
fixed set of forms is not a good idea. Minds on Physics has a nice intro
to
energy where students are presented with various situations and asked if
they would think there is energy. They use bar charts, but I always say
that this is just the energy places we are considering, and you should be
able to add extra categories when needed. Students should learn to use
conservation, rather than just parrot back the "types" of energy.
Actually Modeling has what they consider to be a better idea. Instead of
forms of energy, categorize it according to where you put the energy. This
makes a lot of sense because then students may think about energy as being
one thing, just moved to different places. This helps them understand
conservation, which is the most important concept. When you have different
"forms" of energy it is quite easy to think some disappears during
conversions.
Some states actually mandate things like being able to name the different
"types" of energy, which is just nonsense!!!
I don't hate anyone, just the ludicrous standards and the books which
follow
these standards.
With respect to the burnenergy reference below:
"Chemical energy is stored in the bonds between the atoms in compounds.
This
stored energy is transformed when bonds are broken or formed through
chemical reactions. Like letters of the alphabet that can be rearranged to
form new words with very different meanings, atoms move around during
chemical reactions, and they form new compounds with vastly different
personalities."
NO, NO, NO. This repeats the big misconception that bonds contain energy
when formed. Since it takes energy to stretch a bond (it never breaks or
snaps), it is the stretched (broken) bond that contains energy. Energy is
released when forming bonds. This is one of the most important ideas.
Unfortunately some bio texts containg the verbiage that "breaking bonds
releases energy". Along with this is the misconception that fuel contains
energy. It is the fuel/oxidizer system that contains energy, and the fuel
alone can never supply energy. Now of course the idea of fuel containing
energy is the common everyday concept, but it is not a good one to use in
science class.
"Elastic energy can be stored mechanically in a compressed gas or liquid, a
coiled spring, or a stretched elastic band. On an atomic scale, the stored
energy is a temporary strain placed on the bonds between atoms, meaning
there's no permanent change to the material. These bonds absorb energy as
they are stressed, and release that energy as they relax."
They mention a gas, but there is no "strain" on the non-existant bonds in a
gas. Instead energy is stored as motion. This passage is another that
promotes gross misconceptions. Then of course liquids are usually presented
as being incompressible.
I think that the plethora of misconcepted verbiage on web sites contributes
to the problems with understanding energy. Teachers never learn to look at
the sites critically and say "it presents good basic ideas". Actually most
science teachers will affirm that bonds contain energy.
The third reference "forms of energy" contains some problems. Mechanical
energy is usually defined as a catch all including elastic and kinetic.
Again it has "energy stored in food, fuel". Gravitational energy is not
stored in an object, but in the Earth-object system, or in the
"gravitational field" as it is stretched. It also leaves out internal
potential energy. Leaving it out goes hand in hand with the fact that most
students do not believer that the ice/water interface stays at 0C and that
the boiling water stays at 100C, unusual conditions excepted. They think
the water is at a higher temperature when boiling faster, even though they
have been told otherwise. To understand conventional phase changes you
need
to have a place to put the energy as the temperature remains constant.
This
is where the ILDs are so useful in helping students understand energy.
John M. Clement
Houston, TX
She mentioned standards in several states where they have
interesting acronyms to memorize the forms of energy: SCREAM
- Sound, Chemical, Radiant, Electrical, Atomic, Mechanical
Googling now for other ideas:
http://www.nmsea.org/Curriculum/Primer/forms_of_energy.htm
http://burnanenergyjournal.com/forms-of-energy-motion-heat-lig
ht-sound-2/
http://mskuksclass.weebly.com/uploads/1/9/7/1/19719395/8207568
_orig.jpg
Please don't hate me for showing you these. :)
Paul
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