Re: Weighing Freight Car Models with Liquid Gravity

Tony Thompson

Peter Ness wrote:

For the second part of the statement; If one has two identical cavities and fills one volume with Lead shot and the other with Lead powder, the cavity filled with Lead powder will have more mass than the one filled with shot. Why? The smaller the particle, the higher the surface area and among homogenous material, the smaller the interstitial spacing – all to say there is more mass of powder in the cavity than mass of shot in the other cavity.

       If you use powder, with a range of particle sizes and shapes, sure, no argument. Then you would pack little ones between big ones, and odd-shaped ones into spaces. But if you use actual spheres, the size CANNOT matter. That's all I said.

Tony Thompson             Editor, Signature Press, Berkeley, CA
2906 Forest Ave., Berkeley, CA 94705
(510) 540-6538; e-mail, tony@...
Publishers of books on railroad history

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