The caliper listed at Harbor Freight is a very good deal indeed. But neither it nor a micrometer are usually used to measure film thickness on account of the problems you encountered. There is a device called a thickness gauge used for the purpose of measuring plastic films or thin gauge metal sheet.. It is a dial type device, spring loaded with the film placed between a flat anvil and a ball tip. You slide the film between the anvil and the ball.. The thickness is read on the dial. Digital readout versions are available, but I've never had any trouble with the one I use, nearly 100 years old. There are also ultrasonic thickness gauges. The mechanical ones are usually used now for measuring paint or coating thickness.
--- On Sat, 7/4/09, William Beaty <bi...@eskimo.com> wrote: > From: William Beaty <bi...@eskimo.com> > Subject: Re: [Vo]:Expectation bias, delusion > To: vortex-l@eskimo.com > Date: Saturday, July 4, 2009, 7:19 PM > On Fri, 3 Jul 2009, Stephen A. > Lawrence wrote: > > > No, the force should have been the same in each > trial. Think about what > > you've got. > > > > If each layer is behaving elastically, then the > question you need to ask > > is, what force is needed to compress 1 layer to 1/2 > its thickness? Call > > that force "F". > > Nah, the stuff is really rigid, and the stack visibly > remains flat when > squeezed. (That's probably a good clue that there > were no air layers in > the first place!) It's probably the plastic case > connected to the > micrometer jaw that's flexing, see > http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=47257 > > Wow, they're down to $10 each! They > originally were $50 a few years > back. They have a serial port under a > little door, but it's not a listed > feature, so it might not be alive. > > > > > (((((((((((((((((( ( ( ( ( > (O) ) ) ) ) > ))))))))))))))))))) > William J. Beaty > > SCIENCE HOBBYIST website > billb at amasci com > > http://amasci.com > EE/programmer/sci-exhibits amateur > science, hobby projects, sci fair > Seattle, WA 206-762-3818 unusual > phenomena, tesla coils, weird sci > >
