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Well, here it is: Issue 3 of CoolStuff, the email
Newsletter from Arbor Scientific full of helpful tips, hints, ideas,
suggestions, and fun.
In our last episode, Dave Barnes, our
marketing manager, added the question about Air-Powered
Projectiles to the end of the newsletter. The question was, “If NASA would
only use the Arbor Scientific air-powered rocket propulsion system, how many
students would it take to pump the handle?” Dave is a pilot and like
of us , would love to be launched into space. So, that’s what we’re
going to try to do..... I mean, he’s going to try to answer the question.
Take it away Dave…
Solution-or how I spent my Thanksgiving
Andy’s made me figure this out on my
own…well…almost, with a bunch of help from Space Engineers from around the
country, as well as physics solutions by none other than Mr. Mueller
himself, and our Customer Service Specialist Brian Jacobs.
First I’ll share some of the known
quantities with you. The Air Powered Projectile weighs 3.79 ounces…the Space
shuttle averages about 250,000 lbs. Give or take a few thousand pounds,
depending on the mission configuration. We’ve made numerous assumptions
during this process which will probably become clear as we go along. In this
case, I figured we could leave the solid rocket boosters, and external fuel
tank behind. J
Straight Story on Air-Powered
WARNING! Goggles should be worn and care
taken in the launching of the Air-Powered Projectile as it launches at a
high velocity! Do not lean over the launch pad when pumping the air-pump.
With help from Joe Spaccavento,
Science Supervisor/Physics Teacher of
North Arlington High School in New Jersey and Section Rep, of NJAAPT, we
would like to give you some real ideas for experiments and activities with
the Air-Powered Projectile (APP).
Unlike solid-fuel rockets and water
rockets, which have too many variables for accurately studying Newton's
Laws, this safe, chemical-free air-powered projectile is ideally suited for
exploring projectile motion.
The Air-Powered Projectile is
technically not a rocket. It uses compressed air as “fuel” to power its
launch. One of four thrust washers (sizes Low, Medium, High, and Super) is
pressed onto the top of the launcher and the projectile slides down the
launching tube. Air is pumped into the launcher with the air pump. When it
reaches the pressure needed to launch the projectile, the thrust washer is
forced off the launching tube, sending the projectile into the air.
An example used in many classrooms is
to have students launch the projectile vertically and time how long it takes
for the projectile to complete the trip up and down. This time is then
divided in half to get a pretty good approximation for the time of the
upward portion of the trip. You can then calculate the initial
velocity of the projectile. Then calculate how far the APP will go when
launched at an angle, using vectors. You can even place a target on the
field where you have calculated and hit it.
Click here for
the APP Datasheet for a full explanation.
Cool Pendulum Download
Thanks to Don
Pata, physics teacher at Grosse Point North High School in Grosse Point
Woods, MI for this one. The original author of this program was Ken Appel.
This award-winning teacher teaches physics and AP computer science at
Yorktown High School in Yorktown Heights, NY. Don, being the curious type,
wrote his own as a copy of the original to see if he could do it.
This a Microsoft Excel file. You need Excel to run it. It is a simulation
of a series of pendulums of different lengths and different periods. It is
a top view. You can change the duration and time increment to adjust the
speed of the simulation. It shows how length affects the period, and has
interesting patterns, such as sine waves, dual sine waves, and seemingly
chaotic movement. You can also talk about interference patterns. Or just
watch it like a Lava Lamp. Click here to download the pendulum
Collisions and Energy
Saw this at the last
regional AAPT meeting. From grade school through college, you talk about
energy transformations. Where does the energy go in a collision? There is
no such thing as a perfectly elastic collision, so some of the energy always
gets transformed. Take a Newtonian Demonstrator (Newton’s cradle). Place a
piece of paper between the first and second ball. Pull the first ball up as
high as you can and let go. After the collision, pull the paper out. You
will see a hole that has been burned through the paper. Where does the energy
go as the balls slow down? One place is heat. If you have a very small
version of the device, you may not see much of a hole. If you can get some,
it works really well holding a piece of paper between two large (2 inch
diameter or greater) ball bearings or stainless steel balls and banging them
together with your hands. Click here for info
on ordering a Newtonian Demonstrator
Laser Pointer Games
Laser pointers can be used to show many
properties of light. You can show reflection and refraction with lenses and
mirrors. You can show how color is absorbed. We believe that they can and
should be used in the science classroom for light demonstrations. Yes, you
do need to be careful with them. Don’t shine them in anyone’s eyes. Make
sure that the principal knows what you are doing. Here are some fun
activities to teach about light:
Reflection Laser tag.
We are not suggesting trying to tag
each other with the laser. Make a target. It can be virtually anything, as
long as it will reflect the red laser light. Put it or hang it somewhere in
the room. Place the laser pointer on a steady object and use a clothes pin
or clip to keep the pointer on. (*see hint below) Place a mirror on a desk
and have the students move the mirror so that the laser light falls onto the
target. (Putting on the desk keeps it steadier than holding it.) Move the
target, the laser, or the mirror and try again. Have the students draw the
relationship between the three objects. Add another mirror. Use chalk dust
to show the beam as it reflects off the mirror and show that the incident
angle and the reflected angle are equal. For advanced students or physics
students, you can place the laser and the target first and have the students
calculate where to put the mirrors and at what angle before they try it.
You can also have them hit the target without using mirrors or lenses (think
windows, water, internal reflection, the floor, etc.)
* To make this easier, try our new Laser
Pointer Tripod. It holds a standard pen-style laser pointer. It adjusts to
almost any angle and will hold the button on. It even comes with a Velcro®
strap to attach it to a steady object.
Click here for info on ordering Laser pens
and the tripod
Wile E. Coyote Quiz
When I was teaching, this was my
favorite quiz of the year. This would happen after we covered the force and
motion chapters. Warner Brothers does not seem to keep any particular video
selling for long. I used “Crash Course” which can be found on eBay still.
There are some new tapes out there such as “Scrapes of Wrath” at Amazon.com
or your local discount merchant. I haven’t seen that one, but I would think
it would work. The basic premise is that the students have to identify and
Click here for info on Wile E. Coyote
Some general rules: the Road Runner is infinitely
strong and fast and also has infinite acceleration. Since this is science
class, we are looking for science problems, not reality problems. In other
words, trucks can appear out of pictures, but the Coyote cannot hover. Each
episode is different, but some examples are: Classic Not Falling (CNF), not
enough energy to go higher than started, cannot catch a falling object by
falling, no external force, no normal force, etc. Depending on the level
that you are teaching, the explanations can be simple or more complete.
Physics students should be able to tell how and why a specific law is being
violated. The students have fun taking a quiz!
Did you know that you can find the mass
of air? Using a Pressure Pumper, you can pump up a two-liter bottle and
find the mass of the air that you have added. This is a concept that is
difficult for students to grasp – that air is matter and has mass. Click
below to view the full activity.
Click here for info on ordering
Cool Links and resources
West Point Bridge Designer Contest
years, the United States Military Academy (West Point) has made a program
available for free. You can construct a bridge, test the bridge, and
calculate its cost. It also shows which members have the most stress, and
that the members break when they reach their limits. It is fun as a stand-alone
program. I used it in previous years for students to come in before or
after school to test designs before they built their bridge for our bridge
contest. The winners went on to IIT’s regional contest. For more
information on their international bridge contest, go to:
http://www.iit.edu/~hsbridge/. Go soon, most regionals are at the end
of February. West Point is also having a contest this year with their
program. Students can enter their designs online. Students K-12 can win a
$15,000 scholarship and a notebook computer. The deadline is Feb. 28. Go
for more information.
Physics Christmas Carols ??
Sugar.....Is there a link to Strength?
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