Are you using a block of wood straight from the mill? I had a similar
problem with an experiment until one student who worked in a lumber mill
pointed out that the grain is different for the different faces. Also (at
his mill) the finishing process used on the bigest area of the block is
different than the finishing process on the side or end of the block. I
solved the problem by using a electric sander and 100 (may have been 220)
grit paper on all surfaces. I find that I have to repeat the sanding every
couple of years for good results.
John DaCorte <jdacorte@mdihs.u98.k12.me.us> on 10/29/98 07:53:43 AM
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cc: (bcc: Don Mathieson/SciEngTech/tcc)
Subject: Friction
Hi,
I was wondering if someone could help me with a demonstration I have had
trouble with. I place a block of wood on a tilted desk and tilt it to
the angle that just makes the block move and secure the desk. Then I put
the block on another edge (with a different surface area) to show that the
frictional force and the coefficient of friction do not change with
surface area. The problem is that the block always stays put on the side
with the large surface area and slides on the side with the small surface
area. Any explanations? Thanks in adavance for any help.