OT science project question

"BB" wrote in news:4JSmb.2521$% snipped-for-privacy@nwrddc03.gnilink.net:

So you came back to rmrfor what? An improvement? :)

Note that the first project says he's been unable to actually get any results from it, the second one 'thinks' he might have. Both projects require extreme control of environmental factors...

David Erbas-White

TOO.... FUNNY Jerry you do have a sense of humor no matter what .... anyone.... oops I mean EVERYONE says.....

Thanks for the laugh......

Bobby B

The USGS monitors crustal strain at many locations for volcanic and earthquake analysis.

The following webpage USED to have a discussion of earth tides and their effect on strain data. Its not there anymore (that I could find with a short search), but you may be able to get some info by clicking around. There is data plotted which apparently shows earth tide stresses.

LOL!!

"BB" wrote in news:4JSmb.2521$% snipped-for-privacy@nwrddc03.gnilink.net:

Get two loadcells of the same make/model that will handle a fairly large mass (100 lbs). Make a frame to hold one mass (cement block?) inclined toward the ecliptic (south) and another inclined 90 degrees from it (north), applying their forces normal to the load cells mounted under them, inclined in the same manner. Make sure the load-bearing sides of the masses have minimal static friction (sheets of teflon or mylar oiled). Take the outputs of both load cells and subtract them (intrumentation amps into differential amp). Adjust the offset to read zero, but allow the output to go possitive and negative (test with very small mass added to each one at a time). This set up will cancel the common temperature drifts in the two load cells (same model with very similar temperature coefficients). The one directed toward the ecliptic will see the tidal influence normal to load cell; the other one will have little or no tidal influence (minor tortion?), being orthoganal to the sun/moon. The differencing amp will cancel the common non-tidal drift and amplify the tidal force. Choose a gain that will give a reasonable signal for the expected %change in the weight. Hook this up to a data logger. The reason for the large masses is to dampen vibration. Mount the thing on a thick rubber pad to help isolate it. Also, filter the amp output with a time constant of 1->10 seconds to get rid of more noise (you only want to see relatively long-term affects).

Will this work? I have no idea! :)

(c)2003, John DeMar, all rights reserved, patent pending ;), your mileage may vary, for non-commerical use only, not intended for life-support application, do not eat, keep away from children, do not induce vomiting, don't call me if it doesn't work...

-John DeMar

Um, why not just measure the depth of the water at various times throughout the day for a couple months? You could back out the forces from that to a lot better precision than any lab equipment you're going to hook up at home.

Granted, you're using the ocean as a piece of lab equipment, but it's gotta be easier than this setup, doesn't it?

Alternatively, could you set up some sort of cavendish-type experiment?

Vibration isolation has me worried, though. I never did the experiments, but I know someone who did - he had to have this multi-ton granite block on something that looked like inner tubes. Definitely not high school equipment.

Zooty

sci.astro has been like that for a very long time. You might want to try sci.astro.amateur instead.

The Amateur Scientist hasn't appeared in Scientific American for a while.

You might want to check out The Society for Amateur Scientists . They have information for all sorts of science fair projects. They also sell the CDROM collection of the Amateur Scientist columns from Scientific American.

You could also try Fun Science Gallery . Besides some experiments they have pointers to other science sites.

Brundl, Gary, John, Zoot, Brian & everyone - thanks!

The links and suggestions are proving to be very helpful.

Offshore wind effects (storm surge) would add a significant amount of noise to the measurements. Having a know mass under controlled conditions greatly reduces the confounding variables.

Forgot about that. Good point.

Zooty

I've frequented a few other newsgroups lately, and they make RMR look good on its worst days. It's all that #!^@ Al Gore's fault for inventing this

Bob Kaplow NAR # 18L TRA # "Impeach the TRA BoD" >>> To reply, remove the TRABoD!

Eric Pederson wrote: ...

indeed there are more than 180 known factors which influence the height of the tides. solar and lunar gravity are just two.

I think the 3rd biggest influence on the tides is related to the quantity of hot air produced on RMR.

:-0

Proximity of Chris Taylor?

:-)

Bob Kaplow NAR # 18L TRA # "Impeach the TRA BoD" >>> To reply, remove the TRABoD!

The frequency of Bob Kaplow's rmr posts? ;)

-John