Switchable Magnets.

[synchro1]

Here's a much bettor one. This device is also suitable for Laboratories use and other temperature-controlled systems:

[Pirate88179]

Syncro:

Why not just purchase some Barium Titanate?  Surely this is available commercially cheaper than we could make it in our home labs.

Same thing with the Rochelle Salt crystals?  Isn't there some manufacturer that has a big facility that makes this stuff all day long cheaper, and better maybe, than we could at home?

I am just asking as I have not researched this at all.  Possibly, you have done so and, if this is the case, just ignore my post.

Bill

[tak22]

I like the enthusiasm, but for me an hour of research turned up nothing that talked about being able to achieve a power density for Rochelle Salt Crystals or PZT that would make this worth doing. Have I missed a page or can someone point to a source/research that shows that this is worth anything?  Some real numbers of volts/amps/watts/frequency/pressure/etc Thanks!

tak

[synchro1]

I like the enthusiasm, but for me an hour of research turned up nothing that talked about being able to achieve a power density for Rochelle Salt Crystals or PZT that would make this worth doing. Have I missed a page or can someone point to a source/research that shows that this is worth anything?  Some real numbers of volts/amps/watts/frequency/pressure/etc Thanks!

tak

@Tak22,

Small ones light barbecue fires, what kind of spark would a two kilo brick generate? A mass-pressure to output in watts formula might allow an extrapolation. I'm envisioning two kilo crystals and thousands of pounds of pressure! The "Pyroelectric" effect may be even greater. Imagine a cluster of crystals in a chamber wrapped around an exhaust pipe through which the exhaust gasses are periodically channeled, followed by cooling air. The output might help power a hybrid.

@Pirate88179,

The manufacturing of the "Rochelle Salt Crystals" was a big industry right up untill shortly after WW 2. It disappeared along with the "Stanley Steamer" probably after the same kind of suppressionist  acquisition by John D. Rockefeller. I found 3000 bars of Barium Titanate ceramic that sold at online auction for $2,000,000., but next after that is a disc the size of a "Tea Saucer".

[synchro1]

"To fully appreciate what Moore was up to, you need to understand the Rochelle salt saturation curve in Figure 18. This plot shows the amount of salt that can be dissolved in 100ml of water verses temperature.  For example, with 22C as a room temperature, 100g of Rochelle salt will dissolve in 100ml or water.  That is how I knew that Nicolson's recipe called for 50g more salt than it could hold.

That is not to say that you can't temporarily get more salt into solution than the saturation amount.  If the liquid was at 33C then 150g would completely dissolve in 100ml of water.  Cooled slowly, the higher amount of salt could remain in the solution and it would become supersaturated.   Eventually an impurity of some kind would trigger a spontaneous crystallization and the solution would become simply saturated over time.

The seed crystal also serves as a place where the extra salt can go to get out of solution.  That is how Nicolson's method worked, but the process can go too quickly for the molecules of salt to precisely buildup on the crystal surface.  Starting with a less supersaturated solution slows the process down and that is why Holden and Morrison only call for 9g of extra Rochelle salt.

Another way to slow the process down is to slow the rate of cooling.  When things naturally cool, the rate of temperature change is greatest in the beginning.  Unfortunately that is exactly when you don't have crystal surface to accumulate the salt.  Cooling just 1C from 33C to 32C causes about 10g of salt to leave the mother liquor which is actually a decent sized crystal.  Ideally the temperature should drop very slowly at first and then get faster as the crystal builds.

By accurately controlling the temperature, Moore was able to pace the amount of salt coming out of solution to the growth rate of the crystal.  Starting at 40C, he would only let the temperature drop 0.1C in the first day and then increase the drop slowly every day. He produced crystals about the same size as Nicolson, but it took a month not hours".