Video Transcript
List the four fundamental forces
from greatest relative strength to lowest relative strength.
Okay, to begin putting these forces
in order of strength, let’s start by recalling what they are. In no particular order, the four
fundamental forces, that is, the forces behind all other forces we observe, are
gravity, the electromagnetic force, the weak nuclear force, and the strong nuclear
force. We want to put these forces in
order from the strongest, we’ll say that’s number one, to the relatively weakest,
number four.
One of the nice things about the
names that have been given to these fundamental forces is that the strongest force
actually has that word in its name. The strong nuclear force, which is
responsible for holding the nuclei of atoms intact, acts over only very short
ranges, about the diameter of an average-sized nucleus, but over those distances is
more powerful than any other force.
The next strongest fundamental
force is the one that the strong nuclear force needs to overcome to keep the protons
in a nucleus together. These positively charged particles
naturally want to repel one another via the electromagnetic force.
Now, if we’re unsure of which force
goes here in the third slot, whether gravity or the weak nuclear force, it can help
us to remember that the force of gravity is actually by far the weakest of these
four forces. This can seem strange because, to
our eyes, gravity may be the most apparent of these forces. But nonetheless, from a strength
perspective, it is the weakest, by a lot. This means that our third spot will
be occupied by the weak nuclear force, the force responsible for nuclear decay
processes. And so from strongest to weakest,
the four fundamental forces are the strong nuclear force, the electromagnetic force,
the weak nuclear force, and gravity.
