From: Rilla Chaney (rillac@exploratorium.edu)
Date: Wed Mar 23 2005 - 14:02:35 PST
Message-Id: <43A4D328-9BE7-11D9-B4F7-000A95B5AA1E@exploratorium.edu> From: Rilla Chaney <rillac@exploratorium.edu> Subject: Re: pinhole Recycling and Wind Tunnels Date: Wed, 23 Mar 2005 14:02:35 -0800
I have had a student produce a good wind tunnel with the PVC pipe and
clear plastic window. It worked well enough to lift a balsa wood
airplane wing.
I usually had kids who carved soap cars of different shapes and
attached thin 6-8 inch long ribbons to them at strategic locations.
With a strong fan it is pretty easy to see laminar and turbulent flow
in the ribbon trails. The students can also photograph their different
models in action, make modifications and compare with the earlier
version.
Rilla
On Mar 22, 2005, at 11:47 PM, Raleigh McLemore wrote:
> Recycling: Seems like we should be careful to define recycling. The
> assumption is that it is good for the environment to recycle, but,
> using lead-acid battery recycling as an example, it may only be good
> for our environment. Recycling materials like lead, which according to
> Greenpeace is done increasingly in third world countries, may not be
> good for those in whose environment they are recycled. Some of the
> lead recycling operations in Mexico, for example, are terrifying in
> their output of nearly unregulated lead pollution.
>
> It sounds great, we recycle quite a few of our car batteries, and we
> certainly have enough car batteries to worry over, but my brief
> experience in this stuff makes me very skeptical that we should
> celebrate anything other than our ability to muscle our trash to a
> place where "they can deal with it". This problem makes recycling a
> simpler concept of partial reuse or downcycling and it is not
> neccessarily good for the Earth's environment, although it may make
> people feel good. I am particularly skeptical of old technology,
> lead, oils and paper recycling as possible transfering of our garbage
> to be cleaned up by people who have little to say about receiving this
> stuff. Economic conditions may force people into positions where they
> do hazardous recycling of American wastes, but that isn't the same as
> doing right for our planet. I know we've discussed this before, so I
> apologize for bringing it up again.
>
> Wind Tunnels: I have a student who is working on a wind tunnel idea. I
> can't find a simple working wind tunnel idea, maybe there ain't such
> an animal. It is impossible to line up school administrators ear to
> ear in a straight line to see if that would function as a wind tunnel,
> as any two Oakland adminstrators are unable to face in the same
> direction. I made a really cool wind tunnel using buckets, 6" PVC
> Sewer Pipe (with a clear plastic laminate center tube to observe the
> model) and tried to calm the flow by pulling air through bundles of
> straws at both ends, but the flow is still a mess. Like herding cats.
> I have no idea what to do with this nifty, non-functioning wind tunnel
> except to use it as an example of what quite a bit of effort and
> probably not enough thought can manage to produce. That's science,
> right? Anybody know of a simple working wind tunnel idea? ACME
> Windtunnel Kit might work but I can't seem to reach the Coyote or the
> Roadrunner t! o get the address.
>
> With firm handshake,
> Raleigh
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