If you to look at the
other DEEP projects constructed by our classmates before viewing
this one, you would notice that ours is slightly different. The
reason is that all of our classmates' projects followed a certain
law: Such as Charles, Henrys or Boles law. There were numerous
amounts of experiments that could have been done which follow
these laws. However, Grayson and I chose to construct our own
experiment. We dropped a CD, a spike, a full soda can, and a rock.
This experiment, though it seems very simple, proved many concepts.
We were both fascinated with the concepts of drag, buoyancy, and
resistance in water and air. So, we thought of an experiment that
is explained in method and materials.
If you look at the
results section of our lab, you will probably say something like:
"of course," or "anybody can see that." This
is because people already know it takes the objects longer to
fall through water than it does in air. However, the real reason
for our experiment was to decipher the question of why this happens.
One of the reasons is this. Have you ever noticed that when you
are in water as opposed to in air, you feel much lighter? This
relates to the concept of buoyancy. According to Archimedes, "The
buoyant force is equal to the weight of the displaced liquid."
This means the more dense an object is, the more liquid it will
push to the side of it, thus making it sink faster, or become
less buoyant. you can see this proved in this picture:
Also, in the water
things are more buoyant than in air. Objects which acquire a greater
density do not float as well as objects with less density in both
water and air. So, as displayed in our results, the objects with
more density took much less time to hit the ground than the objects
with less density. This is best displayed when comparing the results
of the CD to the results of the full soda can. The CD, being much
lighter, took a much greater time to hit the ground.
Another factor that contributed to the results we got was the
concepts of aerodynamics and hydrodynamics. Aerodynamic is defined
as an object that passes through the air easier than an object
which is not aerodynamic. Hydrodynamic is defined as an object
which passes through the water easier than an object that is not
hydrodynamic. This is why the skinny spike, which you can see
in the method and materials,took less time to hit the ground in
both the air and water even if it didn't weigh as much as the
full soda can, . The other extreme is the CD compared to the spike
or anything else. Aside from the fact that it was also lighter
than the other objects, it was much less aero and hydrodynamic.
when it fell the air and water was caught under it and slowed
The reason why we dropped
the objects in the air instead of the water is because we wanted
to make the times when we dropped in the air our control. For
us to make any conclusions, we have to compare the results from
the water drop to something. That thing is our results from dropping
the objects in air.
Despite the fact that most of our results were pretty on the mark,
and we got most of the information we needed, there was a great
amount of room for error in this project. The biggest thing wrong
with our project is that we relied on a stopwatch for all of our
results. It is virtually impossible for a human being to stop
and start a stopwatch consistantly and exactly when he/she is
supposed to. This is why the same objects got different times
for different trials. The reason we did three trials is so that
we could take the average of all three and reduce the amount of
error. You can see the percent of error for each object in air
and water in the results section.Through this lab we have discovered
the principles of drag, buoyancy, areo and hydrodynamics, and
the percent and reasons for error in experiments. Overall this
lab we constructed was very educational and lots of fun to do.