On 30.12.2012 13:34, The Natural Philosopher wrote:
....
Ohms law is in any case more a rule of thumb for metallic
conductors.
It never applied to gas discharge tubes or to semiconductors.
Or rather you can say that there are things whose resistance depends
on current and on applied voltage. And in the case of valves and
semiconductors, what's happening elsewhere in the device.
That's the trouble with these 'know a very little knowitalls'.
They stumble on something a bit more than basic and think they have
won the Nobel Prize. They always believe in global warming, too.
I believe in global warming because I was a very clever student.
When I graduated from my university my qualifications in physics
could not be measured. I broke the scale an got 1.0.
I told you about the misery of Ivar Giæver in an earlier message.
It is repeated below because more research is needed to explain
his failure.
One of the first things we were told at university was to remember
that professors are only human and that we should not assume they
are right, simply because they are professors.
None of my professors said that. They all knew that they were at the
top. I am at the top without being a professor.
Accidents can happen. When the The Nobel Prize winner Ivar Giæver
graduated from my university, he got the grade 4.0 i math and
physics. 1.0 was top and 6.0 was bottom. He became a professor by
emigrating to the US where 4.0 was the top.
In the long run the system has a self cleaning property. Quality
floats to the top and stay there, garbage sinks to the bottom and
stay there. Today Ivar Giæver stays at the bottom as a climate
skeptic: http://en.wikipedia.org/wiki/Ivar_Giaever
On 13 September 2011 Giaever resigned from the American Physical
Society over its official position that "the evidence is
incontrovertible."
More research is also needed to explain the failure of
The Natural Philosopher.
Now back to Ohms law:
http://en.wikipedia.org/wiki/Ohm%27s...rature_effects
Ohm's law has sometimes been stated as, "for a conductor in a given
state, the electromotive force is proportional to the current
produced." That is, that the resistance, the ratio of the applied
electromotive force (or voltage) to the current, "does not vary with
the current strength ." The qualifier "in a given state" is usually
interpreted as meaning "at a constant temperature," since the
resistivity of materials is usually temperature dependent. Because
the conduction of current is related to Joule heating of the
conducting body, according to Joule's first law, the temperature of a
conducting body may change when it carries a current. The dependence
of resistance on temperature therefore makes resistance depend upon
the current in a typical experimental setup, making the law in this
form difficult to directly verify. Maxwell and others worked out
several methods to test the law experimentally in 1876, controlling
for heating effects.
Because of the excellent work of Ohm, Maxwell, Heaviside,
Croll, Arrhenius, Milankovitch and others, our world become
very predictable for those that have big brains.
--
jo
There is a tension between short-term, individual welfare
and long-term, group welfare or world welfare.
If it were left to Darwinism alone, there could be no hope.
Short-term greed is bound to win. The only hope lies in
the unique human capacity to use our big brains with our
massive communal database and our forward-simulating imaginations.
From Dr. Dawkins' acceptance speech at the 2001 Kistler Prize Banquet