Suppose, just for the sake of argument,

Xenophile wrote:

> that I wanted to build something that would simulate
> low gravity for children, even teenagers.

If you wanted a device that any DIYer could install
for fun, then probably the simplest thing to use would
be a computer controlled electric servo. This could
counter both the weight of the person, and moderate
the aceleration of gravity. So not only would you
weigh 1/6th your normal weht, but you'd only be
decelerated by 1/6th gravity when you jumped.

> Whatever it is, it needs to be safe enough for
> kids to use,

Impossible. ; )You could never advertise somthing lke
this as 'safe to use by kids'. Most playground
equipment doesn't come with 'adult supervision
required'. ;) Such a device could easily be as 'safe'
as a trapoline though.

> simple enough for non-engineers like me
> to build, and cheap enough for non-millionaires

You can't turn gravity off for pennies a minute. ;) A
cmbinations of pullies and weights SHOULD set you back
several hundred dollars.If it doesn't, it's probably
not safe. The electric-servo soltion would probably in
the multi $1000 range.

> How should I go about it? Pulleys and
> counterweights? Something
> attached to the roof, with a harness for each kid,
> that lets them
> walk along the brick wall of the garage at 1/6th G?
> And whatever it
> is, how do I build it?

Consider that the higher the kid jumps in a pully
system, the more rope will be on the side of the
counter-weight. If you're not careful this increase in
the counter weight will accelerate the child towards
the roof.

ANTIcarrot.

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