Emphasize that the study of
electricity and magnetism revolutionized the world. Have students think
about life without electricity. Ask them what would work without
electricity. They will be surprised to see a very small list. In the
next few labs, students will learn how magnetism, added to principles of
electricity, has shaped our modern society. Students should be very
familiar with the word "electronics". Electronics is the
branch of science and engineering concerned with the theory, design, and
use of devices utilizing electron emission or absorption. Electronics
includes all aspects of photoelectric cells, transistors, circuits,
cathode-ray tubes, electron tubes, oscilloscopes, electron microscopes,
broadcasting, radio, television, telephone, and many other industries.
In 1883, Thomas Edison was studying a
weakness in the filament of his newly developed incandescent lamp. He
placed a strip of metal in the bulb and connected it to a battery. When
the bulb was lighted, he found that electrons flowed from the filament
to the metal strip even though there was no conductor between them.
Edison did not continue to explore this phenomenon which later became
known as the "Edison Effect". This can be attributed as the
beginning of "electronics." Shortly after the beginning of
this century, however, other scientists did perform experiments to learn
more about the Edison effect. Foremost among them were an Englishmen,
Sir John Fleming, and an American, Dr. Lee De Forest.
- Make sure students realize that
electronics deals with the movement of free electrons through
semi-conductor materials which conduct electricity better than
insulators (non-conductors) but not as well as conductors. Show students
a complete chip board and tell them this is why it is called the "
- If you have computer chips
available, have students look under the microscope and see all the
electrical circuits that are on that one chip.
- The main characteristic of all
semiconductors is the resistance to allow electrons to flow. The reason
for this is the crystalline structure of the material. The semiconductor
industry must understand the crystal structure of the materials they use
as semiconductors in order to predict how the electrons will flow to
produce an electrical current. The common semiconductors are germanium
and silicon, and to a smaller extent selenium and tellurium. In
California, the infamous "Silicon Valley" is named for the
most widely used semiconductor in computers
- Use the worksheet to have students
write an essay on the electronics industry. If you live near a
"technology area" you may want to emphasize that area.
Otherwise you can have the students do a search on the Internet on
different electronics company from chip makers, to computer
manufacturers, or any other subjects they come up with. They may want to
ask their parents or neighbors about this industry. If you have a parent
in the industry, invite them to give a talk.