SMS wrote:
My daughter needs to build a marble roller coaster for her physics
class. Most of the class is using pipe foam cut in half, but her team
wants to do rails because you get more points if the design is mostly open.

So she's using stiff steel wire for the rails (my friend had a big
supply of it from old political signs). I was trying to help her figure
out how to support the wire rails at the proper spacing, remembering
that the marble has to be able to roll over any supports. She thought
about using short pieces of PVC pipe as supports, with the rails
attached to the inside. I don't thing cyanocryolate glue would hold well
enough.

I thought maybe drilling small holes in the PVC and using thin steel
wire to tie the rails to the sides.

Any ideas for rail supports welcome. It's okay, parents are allowed to
help!

What size marbles and how long an overall length, etc.?

The wire tie would work but it'll add resistance; if do go something
like that I'd suggest a small diameter filament fishing line or the like
instead of the wire.

Obviously, the best would be if could solder/braze a pre-bent "Y" or
somesuch to the under-side...are they old enough to teach?

Will have to cogitate some more; that's just otoh...

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