BACKGROUND:
How are electricity and magnetism
related? This was a problem that many researchers in the early 1800's
were trying to discover. Michael Faraday discovered how to convert
magnetism into electricity in 1831. This bookbinder learned to read the
books he was binding and became fascinated with chemistry and physics.
Sir Humphry Davy of the England Royal Institute was impressed when
Faraday presented Davy with a book of notes that Faraday made of Davy’s
lectures. Faraday later succeeded Day as Director of the Royal
Institute.
Faraday coined the words electrode,
anode, cathode, electrolyte, and ions which are used to this day.
Faraday developed a continuous mechanical motion produced by electrical
current (a motor) in 1821. He also developed the first electric
generator, and realized that light is an electromagnetic in nature
because it can be deflected by polarized light with a magnet.
PROCEDURE:
- This exercise illustrates
Faraday's Law which states that "the induced voltage in a coil is
numerically equal to the product of the number of loops and the rate at
which the magnetic field changes within those loops". This can be
used to demonstrate the practical side of multiplication.
- When electricity flows through a
wire, the electricity produces a magnetic field. By inserting a core of
iron or steel, the magnetism is intensified. The wire coil wound around
a core is called an electromagnet when it completes a circuit.
Electromagnets are temporary, but used in transistor radios, doorbells
and electric motors. Students will be making an electromagnet in lab.
The worksheet will help them to understand why you need to increase the
number of coils around a wire.
- Use the worksheet to go through
the process of increasing the strength. An electric current can also be
made to flow in a wire by simply moving a magnet in or out of a coil of
wire. This is called "electromagnetic induction". You could
illustrate this with your students with a similar set up as the
worksheet, but it is sometimes difficult to see if you do not have the
correct meter.
- ANSWERS:
1. one
2. two
3. three
