[NewCandle] NR attempt at Fred's battery anti-lifter

[Horace Heffner]

On Aug 13, 2007, at 12:29 PM, Nick Reiter wrote:


>
> Back in the day, I had done some experiments with Sam
> Faile that involved me weighing all individual
> components in an isolated fashion, then putting them
> together in the final "cluster" or arrangement.
> Sometimes the sum of the parts was more or less than
> the aggregate.

I'll try to get this right this time.

If dissolving things (or a chemical reaction is involved resulting in  
a solute, like copper chloride) is part of that process then the  
scale weight is likely to change.  The volume of a solvent and solute  
is often less after solvation than before, but the mass is the same,  
and the density increases.  What changes is the total air displaced  
is reduced, so the resulting solution appears to have "gained  
weight". The amount of gained weight can then hopefully be accounted  
for by measuring the before and after volumes and then multiplying  
the lost volume by the density of air to obtain the loss of  
buoyancy.  That loss of buoyancy makes the aggregate mass appear  
heavier.

How about the effect of water when absorbed into some fibers? The  
fibers swell up by more than the volume of the added water, and thus  
displace more air. The object appears to get lighter.

Horace Heffner
http://www.mtaonline.net/~hheffner/