Weight of Electricity
Does electricity have weight? I know that it is a
force and therefore has no mass, but does that make it completely
weightless? How is that possible?
I think if you really push the issue, you might be able to claim
electricity has some "weight". But it is so hard to measure because
it is so small, and we are using terms in such imprecise ways that
it is easy to get confused. It is on the order of a few electrons.
Electrical force comes from the repulsion of one electron by
another. It might be labeled "electric force" or "magnetic force",
but regardless, that is the source of the force. The electrons have
weight. The force between them is "carried" by a photon, like
light. A photon has a tiny amount of weight, or mass-- it is bent
by a very strong nearby mass, say a star. But it is not bent a lot
by the star's gravity, so the "weight" is very little. Too little
for you to worry about in daily life.
Before considering whether something has weight, you must first know what
weight is. Weight is a force. Weight is how much gravitational force an
object feels. On the Earth, your weight is how hard the Earth pulls on you
by means of gravitational force.
You must also know what mass is. Mass is a measure of how much material an
object is made of. Any object far away from any planets or stars will have
mass but not weight. It is not possible to have weight without mass. If
something felt a force (such as gravity) but had zero mass, the object would
experience infinite acceleration.
Before continuing, consider something. Think of a real-life example of
electricity. Then ask yourself just what gravity would be pulling on. In
most cases, the answer turns out to be the electrically charged particles
that feel and exert the electric force. Quite often, electrons are the
particles involved. "Electricity" flowing through a wire is not actually
electricity. It is a set of electrons flowing through a wire, often called
electric current. Static electricity on a balloon or on a wall is not
electricity. It is too many or too few electrons, causing a build-up of
electric charge. When a set of electric charges are close enough to notice
each other, true electricity is the pushing or pulling between these
particles due to their electric charges. The particles have weight, not the
force between them.
Dr. Ken Mellendorf
Illinois Central College
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Update: June 2012