Cool scientific Java applets

Every once in a while you run across something that reaffirms what a good resource the web is. If you have a bent for physics/science, you should find the following site fun/interesting:

formatting link
as an example, for those woodworkers who need a refresher on how to read/interpolate the vernier scale on a set of calipers or a ruler with decimal place/fractional accuracy, check out the Misc section for java script exercises.

Reply to
Swingman
Loading thread data ...

On Sun, 20 Dec 2009 16:55:22 -0600, the infamous Swingman scrawled the following:

Does it have refresher courses on trig, perchance?

-------------------------------------------- -- I'm in touch with my Inner Curmudgeon. -- ============================================

Reply to
Larry Jaques

Just for those who need a refresher:

formatting link
I missed any favorite formulas, let me know so I can add 'em...

Reply to
Morris Dovey

On Mon, 21 Dec 2009 02:50:43 -0600, the infamous Morris Dovey scrawled the following:

Thanks. But no comment on my requesting math questions from a physics site?

-------------------------------------------- -- I'm in touch with my Inner Curmudgeon. -- ============================================

Reply to
Larry Jaques

Why would that raise any eyebrows? First day in Physics 101 was spent teaching students how to do integral calculus with definite integrals in order to permit teaching the equations of motion. Definite integral calculus was a topic by the way, that wasn't covered in Calculus 101 (a co- requisite with Physics 101) until the final week of the semester.

Reply to
Mark & Juanita

IANAP. The web site has a lot more to do with staying warm and comfortable without being dependent on the energy/fuel sellers.

I've added a few pages for folks wanting to have water to drink, for sanitation, and for agriculture on that same basis.

All the rest is fluff. :)

Reply to
Morris Dovey

Mark & Juanita wrote: ...

Why virtually every engineering curriculum I'm aware of teaches subject-specific math classes outside the mathematics department...several departments went so far at my undergraduate uni as to remove the four-semester calculus/analytic geometry course sequence from their curriculum in favor of doing it themselves in order to at least coordinate the subjects taught and sequence in order to provide the necessary background in time...

--

Reply to
dpb

Morris Dovey wrote: ...

Morris, a wondering/question mixing the two? You ever tried/considered solar stock tank heater in IA winter? Is it even on the cusp of practical???

--

Reply to
dpb

Somebody wrote: ===================================== First day in Physics 101 was spent teaching students how to do integral calculus with definite integrals in order to permit teaching the equations of motion. =================================== My Physics 101 prof was very straight forward on the first day of class.

He stated that periodically he would give "snap" quizes, but not to worry, the answer would always be "1".

Our job was to define the "units" associated with that "1".

Lew

Reply to
Lew Hodgett

I was considering a solar stock tank heater until I looked at these passive geothermal heaters on the Winebrenner farm down in E. Peru, IA:

formatting link
talked to one of their customers. They're reliable, much more simple, and less expensive than anything I could come up with. The customer with whom I spoke buried a run of drain pipe to increase the amount of heat available and said he'd had no freeze problems since installation.

That's at least a good indicator of practicality. :)

Reply to
Morris Dovey

This was an engineering curriculum. Calculus was taught through the applied math department of the engineering college rather that the math department of arts & sciences

I do understand what you are saying here though. Our circuit analysis course spent the first several weeks covering linear algebra & differential equations with s-transform theory. By the time I got to the Linear Algebra & Differential Equations math course TWO semesters later; there wasn't a whole lot of surprise in that course content.

Whatta concept. During my entire undergraduate career, I always had the impression that the PRE-requisite for just about any engineering course I was taking was a full working knowledge of all the material to be covered during the course.

Reply to
Mark & Juanita

On Mon, 21 Dec 2009 14:01:39 -0600, the infamous dpb scrawled the following:

That makes sense.

-- REMEMBER: The sooner you fall behind, the more time you'll have to catch up!

Reply to
Larry Jaques

Thanks for the link...

Looked at it; they only keep the valves from freezing by burying them deeply; water surface still freezes w/o external heat source. Could live w/ that I guess, but the real kicker is they're "large" model is sized for 2-3 head at a time which wouldn't cut it for us w/o a large number of them. We're running 12-1500 head over winter, typically w/ none anywhere during cold weather except on pasture; we sell as feeders to the lots in spring w/ a small feeder operation here while then farm during summer months as have virtually no permanent grass (40A, only, roughly).

So the problem is for the tanks on winter pasture where have no power and are temporary so burial that Cobett uses is out. It's a real difficult chore to keep any propane/gas design have found so far lit in the high W KS wind consistently. Alternatively, chopping ice every morning is _not_ my idea of fun and it takes quite a lot of time not to mention the waste of (albeit solid) water which isn't cheap to pump nor haul the first time what more the multiple the multiple time(s) to replace it. Many days if any bad weather and given short daylight hours the entire day is nothing but hauling water from shortly after dawn to dark... :(

My guess is there's not enough solar heat density to make it practical in size anyway, just wondered if you'd looked into it.

Reply to
dpb

I have, but not for a while - because (in my ignorance) I thought it a solved problem.

The approach I had been working on involved using a solar-powered pump to pump solar-heated _air_ through an immersed tube in an insulated stock tank.

I think it can be made workable, so if you have a little time to collaborate, you're invited to e-mail me directly...

Reply to
Morris Dovey

OK, later on I may do that. Will have to guesstimate what heat load would have to be to have a relatively low level of icing given a tank size. You have any idea what kind of power level you might be talking?

Meanwhile, today I've got to get stuff tied down ahead of the blizzard warnings for tomorrow/next day. We may get somewhat shorted on the snow they say but the wind is certainly coming it appears and if they're only off by a few miles on the snow track might be pretty nasty couple of days. 40+ mph doesn't take a lot of snow to be a pitproverbialappenage. Looks like the brunt may be back towards your area again...

Reply to
dpb

It's fairly difficult for me to do much estimating without a handle on your weather conditions and some info on tank/stock dimensions - for example, I don't have any idea how far a steer can (or is willing to) "reach" for a drink, and that'll be a determining factor for the thickness of insulation that can be used around the tank.

The way to approach his kind of problem is to assume that all the power needed is available, and then design to use it as efficiently as possible - and size the collector to capture whatever turns out to be needed.

Here's hoping you miss the worst of the snow. Our local forecasters are guessing that we'll see more rain than snow in this area, which may make for interesting road conditions.

Reply to
Morris Dovey

.... snip

Best of luck to you. That's not a pleasant task, especially if you are fighting the wind while doing it.

Been windy as all get out here in AZ today also. Rain just started a little while ago -- cold rain.

Reply to
Mark & Juanita

Pretty gentle by our standards today -- about 15-20 from NE this afternoon after the switch from NW a little after noon and the pressure began to drop and the dewpoint obviously rising. About 36-38F mid-afternoon; last heard windchill was in low 20s. Only foggy so far (

Reply to
dpb

Well, they'll reach as far as they can if thirsty, just like they reach under a fence for that delectable blade of grass... :)

About 3-ft is probably practical limit--but you have to count for the water level dropping as they slurp it down, too. Even in cold weather they'll average 3-5 gal/day/head. So far all we've used are the round metal tanks--typically 12-ft diam are convenient to handle/haul and one or two are enough for each location.

Not sure the best estimates for weather to try to use as I think of this more. The problem as I see it on further consideration is that the coldest weather is when the pita factor kicks in the most as that's when if the heaters go out the tanks freeze fastest and thickest so both longer time w/o water and more waste and more trouble. Yet to design for the 0F/30-mph condition would probably be way over what could be practical. I'll have to think some more, Morris and take this offline...

--

Reply to
dpb

Mark & Juanita wrote: ...

...

I had gotten so involved in the "gettin' ready" process had slipped my mind--I had seen the sandstorm on TWC.

It's been a major change here the last 30 years w/ the advent of low- and no-till cultivation, more irrigation and the large acreages back into native grass thru the Conservation Reserve (CRP) that we've not had widescale blowing dirt on the scale I recall in the previous drought cycles (early 50s, in particular; I'm too young for the Dirty 30's) altho there were areas in W OK/N TX panhandles SE CO/NE NM this year that got bad for a while it was much more local than years ago...

It looks like they got shorts all in a wad for nothing over this 'un here, though...we got a dusting this AM but they now have down to 20% chances for anything at all else and no accumulation forecast. Have even backed off on the wind levels as the low just never deepened and is farther north and has a splitoff to the south that prevented the frontogenesis they were so concerned over earlier.

Looks like from Chicago back thru Ioway is where it's all headed...

Sorry for those who do get hit; there's a lot of corn and beans still in the fields back there but can't say I'm at all sorry to miss the blizzard conditions here altho could have stood a few inches of nice, wet snow if it would've stayed on the wheat...

MC, all...

--

Reply to
dpb

HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.