Re: Invention idea--self perpetuating floatation device

From: Uncle Al (UncleAl0_at_hate.spam.net)
Date: 02/28/05 

Date: Sun, 27 Feb 2005 16:15:23 -0800

inertiahero wrote:
>
> My son is in 5th grade and needs to invent something for school.

http://www.uspto.gov/
 6 million ideas

Shoelaces with magnetic aglets so they never drag on the floor.
Compare pole orientations and results. Uncle Al gotta think of
everything.

> He
> has an idea that, while I don’t think is feasible, I can’t really say
> why. Please advise (I'm not a physics guy).

This is one example of why universal suffrage is so untenable - unless
most of the electorate stays home on election days.

> Here's the idea:
> Take a plastic tube, fill with water, seal both ends. Suspend the tube
> at the middle (like a teeter-totter) so it can rock up and down.
> Here’s the tricky part: before sealing tube, put a floatation device
> that, while able to float, is somewhat weighted (maybe a small bobber
> with weights attached). The idea is that while one end is down, the
> bobber will float upward, when it reaches the top, the weight will
> cause the whole tube to rock downward, now the bobber is at the
> bottom and begins to float upwards (back to the other end of the
> tube).

It displaces the weight of its own volume of water. No change.

http://www.lhup.edu/~dsimanek/museum/unwork.htm
 Perpetual motion machines

> The theory is that the tube would rock up and down
> perpetually. My suspicion is that nothing that would float would
> weigh more than the volume of water that’s being displaced by the
> floating object. Maybe this is the real physics question: Is there a
> substance that, while occupying the same given volume of a quantity
> of water—both weighs more than that water, yet will float in water?

No, not passively.

> Thanks for any time anyone give this! 

-- 
Uncle Al
http://www.mazepath.com/uncleal/
 (Toxic URL! Unsafe for children and most mammals)
http://www.mazepath.com/uncleal/qz.pdf