“Don’t forget about your lab tomorrow!”
the teacher shouted as we rushed out of physics to our next classes.
The teacher would do this for many of our labs: warn
us the day before. On the day of the lab, he would tell us the objective and
give us a substantial amount of time to complete it. But one thing was different
about this lab from all of the rest. We had an objective, just like every other
lab, but this time we didn’t have a procedure to follow.
We were given an objective with no procedure. We had the whole class period (because of block scheduling, our classes were an hour and a half long) and
access to anything in the room. Our objective: to create a time-keeping device
that was as accurate as we could get it in the time allowed. We were only allowed
to use a stopwatch in the testing of the device. We would then show the teacher
how accurate—or inaccurate—our timer was.
So, it began.
My lab partner and I thought of different types of time-keeping devices: analogue clocks, digital clocks, atomic clocks,
sundials, and pendulums.
The analogue clock is a 12-hour clock. Some are
powered merely by a battery, which turns the gears, which then make the hands on the clock turn. Some analogue clocks have only an hour hand, while others have a minute hand and a second hand, too. We could not make an analogue clock with the accessible materials.
We couldn’t make a digital clock with the available
materials either. Some digital clocks are 24-hour clocks, while others are 12-hour
clocks. Some are solar-powered, while others are powered by another source. Whatever the power source, an electrical impulse occurs in the device. This constant, electrical impulse is what keeps the time accurate.
We see the time displayed by digits on the face of the clock.
In an atomic clock, atoms bounce off of an object, creating
a certain frequency. This reliable frequency is what keeps the time accurate. We couldn’t make an atomic clock in the allotted time.
The sun casts a shadow onto a dial, creating the time-keeping
device known as the sundial. Being inside, this type of device would not work.
A modern-day pendulum is a grandfather clock. A grandfather clock is similar to the common analogue clock. It
has a power source, which makes a pendulum move at a constant rate. This moves
the gears at a constant rate, which, in turn, moves the hands on the clock.
Since we neither had the materials nor the time to make
a real grandfather clock, most of the groups in the class used the basic pendulum as their time keeping device. Using a string, which we hung from the ceiling, we could create a simple pendulum. Pulling the string back to a certain angle, (this angle was determined by many tests, and it was measured
with a protractor) and letting it go, created a fairly accurate time-keeping device, up to a certain point.