BACKGROUND:
Children are very familiar with the
computer, but many do not know how computers operate. In this lab, we
want the students to look at one of the basic components of a computer,
the computer chip.
The manufacture of silicon that is
used to make chips is a threefold process. The first phase uses crushed
quartzite (SiO2) and coke. It is heated until a commercial
grade of silicon is made. The second phase is when commercial grade
silicon is mixed with methyl chloride to create different types of
silicones. The third phase takes the silicones and hydrogen which then
produces 99.9% pure silicon. It is this silicon that is used in the chip
making industry.
When hot, silicon becomes liquidized,
it can be poured into molds. Usually long cylinders are made of pure
silicon, then cut into thin wafers. The wafer is then "fitted"
with a plastic template and submerged into a vat of acid. This etches
the exposed part of the template, which then acts as tiny electrical
circuits.
PROCEDURE:
- Ask students to list people or
things that use a computer:
a. secretaries - word processing
b. scientists - data
c. airplane pilots - navigate
d. check-out stand - read price of food
e. bankers - read money reports
f. teachers - education
- Hopefully there is a computer that you can
show your students. Point out the parts of the computer. Ask
students what kind of energy is needed to make a computer work?
"Electricity." Can computers work without electricity?
"No!"
- Show them a piece of silicon which is a
human-made element derived from quartz. Microchips are made mainly
from purified silicon. If you have a piece of quartz, show it to
students. Quartz is made out of silicon plus oxygen. It
is used to make pure silicon. The students do not need
to know the entire process, but just so students can see and feel a
piece of the material that makes computer is the important part.
- Instruct students to take the chip
out of its container. Put it carefully under the Swift GH microscope and
have them observe the microchip. On the chip, students are looking at
the etchings. The lines are really a miniature circuit board. Students
should sketch what they see on the lab sheet.
- Show students a circuit
board that you may have gotten from a broken computer or appliance. The
circuit board has many chips that are laid in what is called
"caterpillars." The caterpillars are the black rectangular
objects that have "legs" that are hooked to the circuit board.
The chips are in between the black layers.
Hopefully now, students will know how
"Silicon Valley" in California gets its name!
