An Exhibition In Energy  Resource Page
When first contemplating the idea of developing a science show with energy as the main theme
we were at a loss in deciding what demonstrations to present. But it finally occurred to us that
any demonstration with some physical basis is fundamentally tied to energy - whether the
science be physics, chemistry or even life science.

But what is energy?  I know often when I rise in the morning to get ready for work I’m lacking
much of it. The word 'energy' is used casually in everyday conversation but if we stop for a
moment and really try to pin down a more exact definition , it immediately escapes our grasp –
much like trying to define what time is. Energy fits into that category of things you can
certainly name but not touch or hold in your hand. Is energy real or just a convenient invention
of the human mind to better help us  to explain our perception of nature?  In Einstein and
Infeld’s popular book “The Evolution of Physics” Einstein said that all substance considered in
the universe fits into either matter or field. Matter has mass, but field has no mass. Fields
represent energy and matter represents mass. Einstein’s work in special relativity initially
addressed the electrodynamics of moving body’s however led to a quite remarkable and
unexpected result; the famous equation that everyone is so familiar with:

                                                          E = mc2.

This equation tells us there is a quantitative relation between matter and field; mass and
energy. That lead Einstein to question if field was the only reality. Could matter just be some
condensed form of energy?  If you ask today’s physicists for a definition of energy: ”Energy is
the ability to do work.” Well that at least explains why it’s so hard to get to work in the
morning.

Energy is a very fundamental concept. Newton’s second law says that where we have motion
there are net forces. But energy is first required to generate force. Motion is evidence that
energy has flowed from one place to another – not that it was just spent or is now gone. When
energy is used to perform work and cause motion it does not just disappear. Its affects are
either transferred outside the local ‘system’ into another or converted to another form of
energy within the same system. But energy is never lost; its always conserved. When our
automobile moves along the road it carries with it kinetic energy. The automobile is the local
system being considered. When we need to suddenly brake, where did the energy go? The
brakes apply friction within their internal surfaces and the tires apply friction to the surface
of the road. From each of these surfaces heat is generated. All (or at least most) of that kinetic
energy was converted to heat and transferred - heating the brakes, the surface of the road and
the air molecules near the brake surfaces. It would take very close accounting, but with enough
diligence the energy can all be accounted for. That’s conservation of energy.

Imagine a universe without energy. Such a universe would be a very cold, dark and uninteresting
place. Our universe abounds in energy - in every nook and cranny from the smallest particles we
can imagine to the motions of galaxies making it a really interesting place to exist. But the
distribution of energy throughout the universe varies enormously. There are ‘voids’ between
galaxies that closely approach the cold dark place described above. But even these voids appear
to contain a minute fraction of energy. Then there are the places where the concentration of
energy is so great it’s almost unimaginable compared to what we experience on earth or even
within our own sun. Deep within the center of our Milky Way galaxy, and very similar to most
other galaxies we have been able to observe, there lays a giant sized black hole. A black hole
consists of matter that under its own weight has been stripped of its electrons reduced to a
nuclear soup. The mass of the balck hole its gravity causes anything near it to fall in and
become part of that soup. The black holes at the center of galaxies are special black holes that
fit into the category ‘supermassive’. These supermassive black holes provide energy that gives
rise to forces causing turbulent and chaotic motions among orbiting stars that accelerate them
to near light speeds.  Some are consumed by the black hole, others are flung away at high
velocity.
To gain a perspective on the scale
of the universe, click on the
constellation above
Counter
CHECK BACK SOON FOR UPDATES
Larry Sverdrup
and Mike Borrello