Answer 1:
I did some research online and could not find
anything that becomes a magnet when it
conducts electricity. This doesn’t necessarily
mean a special material like that does not exist,
but I think
it makes sense that a material that becomes a
magnet upon conduction would be hard to make.
Here’s
why:
There are two types of magnetism: intrinsic
magnetism which is caused by the “spin” of
electrons and
induced magnetism which is caused by the motion of
electrons. (Electrons don’t actually physically spin.
Spin is just a fundamental property of electrons
from quantum mechanics, like the way charge or mass
are properties. Physicists called the property
“spin” because the way spin factors in to electron
interaction is kind of like how the angular
momentum of rotating objects interacts. For this
explanation
all you need to understand is the spin gives
electrons, among other things, a fundamental magnetic
moment)
The magnets one typically thinks of when they
imagine magnets are a set of magnetic materials called
ferromagnets. These are a special class of
materials that retain magnetic moment even when
there is
no external magnetic field, and they do this
through intrinsic magnetism. In quantum mechanics
electrons can either have a “spin up” or a “spin
down” and when an up and down electron are paired
together, their magnetic properties cancel out.
Normally electrons like to pair up, but in some
materials
one or some of the electrons are left without a
mate. This net imbalance of ups and downs can create a
magnetic field, and in the case of a ferroelectric
material, all of the magnetic grains created by this
imbalance want to lie parallel and stay parallel
when a magnetic field is applied. Because the grains
want to stay pointed the same direction, a
ferromagnet remains magnetic in the absence of a
field
.
However, you can also create magnets though the
movement of electrons (i.e. current). These are
called electromagnets. When current runs through a
wire, it creates rings of magnetic field. When you
loop a wire many times around a metal, all of the
little magnetic fields from the loops of wire line
up and
induce a larger field in the central metal. You
can actually make an electromagnet at home with a few
supplies.
Check out how in this video! click
here to watch The
important thing to understand here, though, is
that the metal that becomes the electromagnet isn’t
actually conducting any electricity, only the wire
around it is.
The reason it would be hard to make a material
that turns into a ferromagnet upon conducting a small
amount of current is that you would have to find
some way to have current affect the direction the
magnetic grains are pointing (or possibly have
current activate the grains?) and as far as I
know, the two
are not normally coupled that way. But perhaps you
will find a way to connect them in the future! |