[Music]
In 1820 danish physicist and chemist
Hans Christian Oersted with setting up
materials for a lecture. His materials
included in early kind of battery called
voltaic pile constructed of copper and
zinc plates in a dilute acid solution and
a wire held in place here by a set of clamps.
Oersted and other scientist of his
day knew that when a wire was connected
between the positive and negative
terminals of the battery electricity
would flow through that wire. Electrons
actually move from negative to positive
however the convention is to think of
electrical current as moving from
positive to negative so that's how we'll
show it here using red particles.
Back then scientists still have much to learn
about electricity. Preparing for his
lecture, Oersted made a very important
discovery about the phenomenon quite
accidentally. Among Oersted's scientific
paraphernalia with a compass. It's needle, of
course, pointed north in alignment with
the Earth's magnetic field.
Oersted happen to place the compass
near his battery and was startled to notice
that the compass needle moved.
As Oersted deduced, this happen because the wire
producing magnetic field around it when
it carried a current. If there is no
current in the wire the needle reverts to
to aligning with the Earth's magnetic
field.
As it turns out, an electric current made
up of moving charged particles, produces
a magnetic field that circles around the
moving current shown by the blue lines. If
you reverse the direction of the current
then the magnetic field around the wire
moves in the opposite direction and the
needle on the compass flips to reflect
the change in field. If you move the
compass to a new spot near the wire, the
needle will realign with the direction of the
magnetic field in that particular
location.
Oersted's accidental discovery with solid evidence that electricity and
magnetism were related phenomena the
announcement of his findings incited a
tremendous outbreak of research in the
nascent field of electromagnetics in the
early 1820's.
[Music]
