This activity allows for students to measure the wind speed and
interpret their data on the
Beaufort scale To begin this activity, the teacher
may want to explain how the
kestrel works. – This is a kestrel wind meter.
Scientists use this in the field to measure wind speed. In this
activity, we will be using a couple different options on this
device. We want our device to be set to maximum. You
can scroll through the different measuring speeds. You can go maximum, average, or
spontaneous. And we want
it in miles per hour. And to change the units,
you hold the middle button
down and click the right. So we want miles per hour and maximum speed. – Now
allow the students to measure
their wind speed, and guide them through the use of the of
the chart. – So how windy am
I? [blowing] Thirty four point five miles per hour! – Now go ahead
and find your wind speed on this chart. – Okay. So how
windy am I? I was thirty four point five miles
per hour. Ah! That puts me down here. I am
a moderate gale! If there were more of me and we
all blew at the same time, we could put trees in… What’s
this number over here? This
number represents the Beaufort scale number. So we
can classify your wind speed between a range
of thirty two to thirty eight miles per hour, and
we would classify it as a seven on the Beaufort scale.
– Please take a moment and
answer the questions. Why don’t wind turbines work
with too little or too much
wind? – And the answer is… We were a seven.
– Yes we were. – Thirty two to thirty eight,
moderate gale, and that’s in the bright green area! Do you want to
explain about these different
colors? – Ya! Well as you can see, there’s two red
areas, one at the minimum and
maximum of the Beaufort
scale. Why do you think we’d have a red area at the
minimum area? – I think that one’s easy to know,
that it just doesn’t have enough power at that point to make the
turbine spin. Those blades are pretty big. So it
probably doesn’t start, or as we say, cut in, until it gets at least
to this first green one, which is what’s
the range there? – Eight to twelve miles per hour.
Now what about the other end
of the spectrum? What about the high winds? – You
know, those are really expensive machines. The last I
heard, they were about a
million dollars per megawatt. So those are pretty
expensive machines, and you
would not want them to be damaged! And
so I would suspect that when the wind gets really
really bad, they’re going to shut them down because they
want to protect them. So I see that that’s what we’ve got right
here. Where we call this the
cut in speed, this is the cut out speed.