Floating Water
Final Report
Table Of Content
INTRO
PROJECT DISCRIPTION
FUTURE WORK
CONCLUSION
BIBLIOGRAPHY
ACKNOWLEDGEMENTS
Our project determines the time and
distance virga takes place. Virga
like we explained in the summary, is the phenomenon of falling rain that
we see but never reaches the ground. By analyzing the suspended drops in
our wind tunnel we will see the differences of the time the drops take
to disappear, by the shape and the wind speed. Our wind speed will be a
constant of 849.5 rpm's. We will have to use more or less screens to
change the wind speed. Barry brought the design of the wind tunnel to us
in a book he was reading. We sort of did the blue print out of nowhere
because all we had was a picture. We constructed the wind tunnel at
school and painted it at school.
Our computer program will predict the time
the drop will disappear and
at what speed did it disappear. It will also, if we can, predict its
volume and it's shape while in air and at what times it will change. We
will use different size of drops and see the differences and the shapes
they make. The results of our test will be used to draw conclusions
about virga.
After studying virga and its effects, we
have better understanding of
why virga happens and how.
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Our group is going to study motion using photography and a drop of
liquid. We will incorporate a drop of water suspended in a vertical wind
tunnel. We will take pictures of the drop at different wind speeds and
drop sizes. The pictures will then be analyzed by us and studied. We will
then use the pictures to see the differences of the drops by shape and
speed. We will then use that data to make a c++ program to calculate the
drops shape and its change in form at the different speeds. Our reason for
this project is to determine the conditions on which virga can occur.
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The United States Air Force supplied us
with all the materials for the
wind tunnel. Our group will have to get permission from the Air Force in
order to obtain the wind tunnel.
After clearance is given by the Air
Force, the wind tunnel will either
be donated to the science department of Bernalillo High School, or it
will be used for future A.i.S. Challenges. We would like students at our
high school to get an opportunity to benefit from such a diverse way of
learning.
If the wind tunnel is used for future
A.i.S. Challenges, our group
will expand further on the topic of motion with water droplets, through
the Internet and e-mail exchanges with students from around the state
who are also interested in the same topic.
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The results from our experiment are
inconclusive so far. Our original
design did not work so we are still trying different modifications. The
four to five screens that are suppose to control the air speed and the
turbulence have proved to be too much resistance for the amount of air
speed our fan puts out. We pulled two of the screens out, redesigned the
third, and by taking out the bottom half of our wind tunnel we have
increased the air speed to hold the drop in mid-air. From our trial and
error techniques we can see the basic shape of the drop as it falls. We
have seen the effect of virga on the drop as the wind surrounds the
forming water droplet. The effect doesn't take more than a few seconds
to take place and as it does, controlling the drop becomes more
difficult.
The drop forms a dome shape as it falls
from the dropper which makes
it hard to control. If the drop forms too large the shape is more like
a flat bubbly plane. At that point, the strain on the drop is too much
for the surface tension to hold it together. As the larger drops float
around much like a puck in air-hockey it slides around quite a bit until
it breaks up into smaller drops. The smaller the drops are easier to
control, but they don't last long due to the virga effect. We are
continuing the experiments until we produce more accurate results.
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http://www.mit.edu
http://www.rit.edu
http://www.go2net.com
http://www.grainger.com
Dr. James E. McDonald
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Our group would like to thank the following individuals:
Mr. Barry Berendberg
Ms. Ronda Cole
Ms. Candace Martinez
Ms. Jennifer Coughlin
Mr. William Brooke
Thank you for all your help and dedication, Which was essential in
making this project a success.