Energy and Form of Matter
Is energy a form of matter? My school teacher
says so by quoting E=mc^2 relation. But by definition the matter
should have mass, shape and size; and it should be localized. I
am not convinced, and am confused. Please clarify.
You have made some assumptions about the "properties" of matter
that are not universally correct. Matter does not always have a
specific shape (liquids take on the shape of the vessel containing
the liquid), nor is matter always localized (a gas occupies both
the shape and the size of the vessel containing the gas, so it does
not necessarily have a specific fixed location). Even solids do not
have a specific size (the size of a solid depends upon its
temperature and the pressure that is exerted upon it, and can
change shape by stretching, bending etc.).
There are many experimental results confirming that "energy" and
"mass" are equivalent, although the enormous equivalence factor
(c^2) means that under "normal" conditions the two seem to be
distinct. Two direct results confirming that equivalence are: 1.
the annihilation of an electron and its anti-particle the positron,
produces electromagnetic radiation whose energy is precisely the
given by the relation E=mc^2. The second result is nuclear fusion
and fission in which energy and mass are not individually
conserved, but rather it is the collective mass/energy together
that is conserved. There are thousands of examples verifying that equivalence.
I think that it is the fact that in our "everyday" conditions
that energy and mass appear to be distinct quantities, but it is
the size of (c^2) that makes this appear to be so. Under the proper
conditions the equivalence can be demonstrated.
The proper way to state it is, "Matter is a form of energy." Energy has
many locations. Energy is in the temperature within matter. Energy
is in heat
as it transfers from one material to another. Energy is in the motion of an
object. Energy is in the force between objects, even the force between
atoms. Energy is in light.
Albert Einstein discovered that energy is in the mass of an object. When
that energy is released, when mass is converted into a more familiar form of
energy, the units of energy equals the units of mass multiplied by c^2, or
(3.00x10^8 m/s^2. This released energy is usually as light or heat. These
tend to be the easiest to create and the most difficult to control.
A way to see that mass is a form of energy is to consider a proton.
Scientists have discovered particles known as quarks. Quarks have almost no
mass. The mass of up and down quarks are much less the mass than electrons.
A proton is made of two up quarks and one down quark. The quarks move
around very much. This is kinetic energy. The force between the quarks is
the "strong force". This force is considered to be the strongest force in
the universe. The strong force has potential energy, just as gravity and
spring forces do. We see the total of these internal energies as the mass
of the proton.
It is more accurate to say that matter is a form of energy; mass IS
energy! (A little bit of mass is a lot of energy.)
In response to your objections: does matter really have shape and
size? The shape and size we observe of material objects is a
consequence of forces between elementary particles so small that
there is so far no evidence that they actually have any size. And
as for being localized: the only reason particles can be localized
is because their masses (rest energies) are so large. There's
always some indeterminacy of the location of any object due to the
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Update: June 2012