"Why do the iron wires, which originally were not magnetic, become magnetic after stroking them with one end of the bar magnet
? Please use the dipole small-magnets model to explain why the iron wires would become magnetic by considering the similarities and differences between the magnet and the iron wires."
A long magnet was constructed by joining two large bar magnets
together (using their mutual attraction) and then adding two smaller bar magnets
, one at each end of the large-magnet bar.
Or, he/ she might ask questions of the learner so that the latter may clarify reasons for learning about "magnetism" and "electricity." Here the pupils may use bar magnets
to establish ideas pertaining to the north and south pole of a magnet.
Like a compass needle repulsed by a bar magnet
, the large external field repels the frogs' small field sufficiently to counteract gravity.
wand or bar magnet
Step 1: Measure 125 ml (1/2 cup) of the cereal and
Ampere also demonstrated that a current flowing through a wire bent into a helix (similar in shape to a bed spring) strengthened the magnetic effect with each turn of the wire, and the helix clearly acted like a bar magnet
with a north pole and a south pole.
The material to be treated is conveyed through an electrode array where an RF alternating energy field causes polar molecules in the material to continuously reorient them to face opposite poles much like the way a bar magnet
would behave in an alternating magnetic field.
They also show that each chondrule is magnetized like a little bar magnet
, but with 'north' pointing in random directions," Desch said.
"Each fundamental particle behaves like a very tiny bar magnet
or compass needle," explains Stefan Ulmer, a particle physicist at RIKEN in Wako, Japan.
A cycle starts with the Sun's magnetic field weak and dipolar--like a giant bar magnet
. Our star rotates fastest at its equator, and this differential rotation wraps the magnetic field lines like rubber bands around the solar surface.
It's as if a bar magnet
slowly lost its magnetic field and regained it in the opposite direction, so the positive side becomes the negative side.