Date: Wed, 01 Sep 2004 10:33:22 -0400

Author: Tom Ford

Subject: RE: safety?

Post:

Why would you need tracks for this? Two 2x4's spanned by plywood with skate
wheels lagged to the sides will rocket across the gym (one "squirt" per
student). A pair of these on the lab floor, or even better on a long bench,
help convince students that forces come in pairs. "Today we are going to
study explosions!" -- gets the students interested. One or two students on
each cart, using hands for bumpers. One team is told to push, the other to
NOT PUSH BACK, and then roles are reversed. Forces are not formed by
"intention," and always come in pairs, acting on separate bodies.

Tom Ford

At 11:06 PM 8/31/04, Dick H. wrote:
>Greetings
>
>Look around to see if someone is replacing their sliding porch door.
>There is metal framing which the sliding door fits in. I ended up with 4
>pieces, two from the top and bottom which were longer than the two
>vertical pieces.
>
>Excellent track. As to the carts, I used a piece of 1 inch plywood taken
>from cabinet bases when Penny's remodeled. They are 20 x 30 inches in
>size. For wheels, I cut in half some old wooden PSSC carts with roller
>skate wheels. I used the end with one wheel and just fastened them, one
>to each corner of the board.
>
>Fastening a rubber bungee cord to one end, stretching it a given amount,
>it will easily accelerate with a person on it.
>
>Sitting on the cart with a fire extinguisher pointing backward, it
>obtains a nice acceleration.
>
>I could take a picture and put it on my web site if some wants to see
>it.
>
>Dick
>
>"Science is nothing more than learning how to communicate with nature in
>such a manner that it will talk back."
>
>Helping teachers who facilitate, motivating students who learn.
>Dick Heckathorn 14665 Pawnee Trail Middleburg Hts, OH 44130
>440-826-0834
>Physics Teacher CVCA 4687 Wyoga Rd Cuyahoga Falls, OH 44224
>330-929-0575 VM 120
>
>
>-----Original Message-----
>From: owner-tap-l@listproc.appstate.edu
>[mailto:owner-tap-l@listproc.appstate.edu] On Behalf Of sampere
>Sent: Tuesday, August 31, 2004 1:58 PM
>To: tap-l@listproc.appstate.edu
>Subject: Re: safety?
>
>I'm just using c-channel aluminum for the body of the car and the
>track.. The track is 10" wide x 8' long and the car is 8" wide.
>
>I'll post pics when it's all finished. Man, I owe you all a lot of
>pictures!
>
>Sam
>
>Michael Timmins wrote:
>
> >How are you making the cart and track? A friend of mine years ago who
> >is into making movies built his own camera track from two long parallel
> >pieces of 3" or so pipe with a cart that had pairs of skateboard wheels
> >set in a V which ran very smoothly along the track. I always though
> >this might be a good method for doing 1-d dynamics.
> >
> >Mike
> >
> >On Tue, 2004-08-31 at 11:27, sampere wrote:
> >
> >
> >>That's exactly what I'm doing Jason, essentially scaling up my
> >>existing Pasco equipment. You know how we always bitch about not
> >>having a horizontal oscillator? Well, if the cart is massive enough,
> >>then the spring can be made to be self supporting and you can have an
> >>oscillator at reasonable frequencies. Cool, et?
> >>
> >>TTFN,
> >>
> >>Sam
> >>
> >>p.s. aren't you in graduate student mode yet?
> >>
> >>Jason St. John wrote:
> >>
> >>
> >>>I'd like to have a pair of carts and a track for them. Most students
>who
> >>>are in classes where they see collision carts in lecture also do
> >>>computer-based labs with them. I'd love for the lecture
>demonstration set
> >>>to be larger and more visible than the carts they use in their labs.
> >>>
> >>>I wonder if it would be better for the giant carts to be a little
>less
> >>>massive than a simple scale-up achieves; cart-mounted fans, springs,
>even
> >>>strings with tension are all used to apply forces to the carts, but
>they
> >>>may fall short of the magnitudes of force needed to get a massive
>cart to
> >>>accelerate well. Then again, with some demos, it would be nice to
>have a
> >>>giant cart which isn't so responsive to external forces.
> >>>
> >>>What about a whole scaled-up, lecture-hall-sized set of PASCO
>dynamics
> >>>equipment? A ballistic cart that size would be great!
> >>>-jmsj
> >>>____________________________________________________
> >>>Jason St. John 617.353.2634 stjohn@bu.edu
> >>>Boston University Physics Lecture Demonstrations
> >>>Room 255, 590 Commonwealth Ave. Boston, MA 02215
> >>>
> >>>On 2004-08-31.08:10 owner-tap-l@listproc.appstate.edu sent:
> >>>
> >>>I want a giant Pasco cart, too. JZ
> >>>
> >>>At 08:58 PM 8/30/2004 -0400, you wrote:
> >>>
> >>>
> >>>
> >>>>Sorry, I guess that was worded poorly. I'm having my machine shop
>build it.
> >>>>I was just thanking Pasco for that great idea. I don't know why I
>didn't
> >>>>think of it before, what, with having a 1 m diameter VdG. Go
>figure.
> >>>>What else should we 'giantize'?
> >>>>
> >>>>Just out of curiosity, how many of you would like the giant version?
> >>>>Pasco, are you listening?? I think that set would be a great
>addition to the
> >>>>catalog.
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>>I did win a prize and my giant version of a Pasco cart and track
>are in
> >>>>>production! I can't wait to use these babies in the auditorium.
>Watching
> >>>>>Doherty was the highlight of the demo show IMO. I wish he was
>allotted more
> >>>>>time!
> >>>>>
> >>>>>
> >>>>>
> >>>Gerald Zani e-mail: Gerald_Zani@brown.edu
> >>>Manager of Demonstrations phone: (401) 863-3964
> >>>Department of Physics FAX: (401) 863-2024
> >>>Brown University Providence, RI 02912-1843 USA
> >>>
> >>>http://128.148.60.98/physics/demopages/demo/
> >>>http://128.148.60.98/physics/userpages/staff/Gerald_Zani/index.html
> >>>
> >>>Do a little more of that work which you have confessed to be good,
> >>>Which you feel that society and your most Just Judge rightly demand
>of you.
> >>>Cultivate the tree which you have found to bear fruit in your soil.
> >>>If you have any experiments you would like to try, try them.
> >>>Now's your chance.
> >>>
> >>>Henry David Thoreau, Journal entry, 1850.
> >>>
> >>>
> >>>

From stjohn@buphy.bu.edu Wed Sep 1 10:23:16 2004

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