General science thread

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January 30th, 2017 at 1:52:55 PM permalink
Face
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Just to clarify, I'm not sure that the "breaking of the crystals" has anything to do with the reaction. I've only had them a few days so no in-depth testing, but... the best way I can explain (if it's even correct) is to compare it to gum.

The pack is like gum. It has the ability to release heat just as the gum has the ability to release flavor. If you were to chew gum to "activate" it and then just suck on it, it loses its flavor very quickly. You can still taste it slightly, but the real punch doesn't come until you agitate it more to get to the flavor stored inside. The pack seems similar in this regard. If you don't break them up, it gets stiff and is quite warm, but not hot. Agitating it doesn't seem to "activate" it, rather it seems to just get the stuff on the outside (which has lost some heat) mixed back in and allows the stuff on the inside (which still has all its thermal energy) on the outside where you can feel it. That make sense?

And Aye, I tried other ways of activation. My very preliminary hypothesis was that the act of boiling added enough energy to break down the bonds of the solid of the pack, but whatever liquid it was was very unstable. An intro of energy, in this case kinetic from the cap, was enough to start the chain reaction, similar to striking a blister of nitroglycerine with a hammer. I didn't get too crazy as I'm really digging this miracle, but I punched and flicked it in an attempt to introduce the same snap of energy, but it was for naught. The cool liquid stayed liquid and cool.

Fortunately I took a puck to the calf last night. Time for more testing =)
Be bold and risk defeat, or be cautious and encourage it.
January 30th, 2017 at 1:59:22 PM permalink
Nareed
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Quote: Face
My very preliminary hypothesis was that the act of boiling added enough energy to break down the bonds of the solid of the pack, but whatever liquid it was was very unstable.


If you boil anything, you add energy to it. How much you add depends on how much it can absorb. Once added, though, the energy will go somewhere. In the case of heat, it will go to the thing next to it if it's colder, unless the energy can be stored in a form other than heat.

Consider a rechargeable battery. It absorbs electromagnetic energy when you charge it, but it doesn't store it as electromagnetic energy. if it did, the battery would discharge in short order (unless it were perfectly insulated). Instead it converts electricity to chemical energy, which is more stable and can be discharged (to power your phone) in a more measured way over a longer time.
If Trump where half as smart as he thinks he is, he'd be twice as smart as he really is.
January 31st, 2017 at 9:34:19 AM permalink
rxwine
Member since: Oct 24, 2012
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If you want to help search for archeological sites, now you can.

Quote:
Users of the site will be given a tutorial showing them what different patterns on images mean. When six people flag an area of potential interest, it will be handed over to Dr Parcak's team to assess whether it is an area worthy of exploration.

The website will also allow citizen archaeologists to spot potential looting of existing sites, which is becoming a huge problem in sites around the world.
And to make sure looters do not use the site to locate potential targets, the high-resolution satellite images are broken into tens of million of small tiles which are displayed to users in a random order without the ability to navigate or pan out. The tiles do not contain any location reference or co-ordinate information.


Only in Peru, so far.

http://www.bbc.com/news/technology-38812526
No one has ever proven I am not God.
January 31st, 2017 at 12:53:21 PM permalink
Nareed
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This is interesting: http://www.symmetrymagazine.org/article/sign-of-a-long-sought-asymmetry

The results are very preliminary and not, yet, statistically significant. But they suggest where to look. This might, in time, lead to an explanation as to why there is a lot of matter and only a little anti-matter. cosmological theories suggest they should have been appeared in equal amounts at the Big Bang.
If Trump where half as smart as he thinks he is, he'd be twice as smart as he really is.
February 1st, 2017 at 3:28:23 AM permalink
odiousgambit
Member since: Oct 28, 2012
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Quote: Face
Time for more testing =)
this is some gadget you got from some store or the internet, right? I in fact cannot get such to come up in google.

Mustard:You like Kipling, Miss Scarlet? Sure, I'll eat anything [from movie]
February 1st, 2017 at 12:01:09 PM permalink
rxwine
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BATBOT (were you told bats will fly down and get tangled in your hair?)

No one has ever proven I am not God.
February 1st, 2017 at 2:30:04 PM permalink
Face
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Quote: odiousgambit
this is some gadget you got from some store or the internet, right? I in fact cannot get such to come up in google.


It was a gift from a friend who acquired it from one of those MLM sex toy parties lol. I reckon it's for "sensual massage", but it does up torn ligaments a treat!
Be bold and risk defeat, or be cautious and encourage it.
February 1st, 2017 at 4:54:47 PM permalink
odiousgambit
Member since: Oct 28, 2012
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Quote: Face
It was a gift from a friend who acquired it from one of those MLM sex toy parties lol. I reckon it's for "sensual massage", but it does up torn ligaments a treat!


https://en.wikipedia.org/wiki/Heating_pad The most common reusable heat pads contain a supersaturated solution of sodium acetate (3H2O CH3COONa) in water. Crystallization is triggered by flexing a small flat disc of notched ferrous metal embedded in the liquid. Pressing the disc releases very tiny adhered crystals of sodium acetate into the solution which then act as nucleation sites for the crystallization of the sodium acetate into the hydrated salt (sodium acetate trihydrate). Because the liquid is supersaturated, this makes the solution crystallize suddenly, thereby releasing the energy of the crystal lattice. The use of the metal disc was invented in 1978.

The pad can be reused by placing it in boiling water for 1015 minutes, which redissolves the sodium acetate trihydrate in the contained water and recreates a supersaturated solution. Once the pad has returned to room temperature it can be triggered again. Triggering the pad before it has reached room temperature results in the pad reaching a lower peak temperature, as compared to waiting until it had completely cooled. ........... note that this says the heat is released when the crystallization occurs, which you seem to contradict
Mustard:You like Kipling, Miss Scarlet? Sure, I'll eat anything [from movie]
February 2nd, 2017 at 3:29:03 AM permalink
Pacomartin
Member since: Oct 24, 2012
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Quote: Face
Do not Google this and ruin my game...


I will put in a spoiler. Primary products for Back, Foot , and Neck & Shoulders are $75, but there are smaller products like a pocket warmer for $13.

http://www.clickheat.eu/The-Products/CategoryID/7/ProductID/26.aspx
February 23rd, 2017 at 9:13:49 AM permalink
Nareed
Member since: Oct 24, 2012
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NASA announced yesterday the discovery of a system with seven "Earth-like" rocky planets, some of which are in the star's "goldilocks zone," where liquid water can exist and temperatures are compatible with life as we know it.

This is all very nice, but don't get too excited. The star is a red dwarf (need I say more?) Sure it makes sense to set some SETI assets to listen, but temper your expectations.

What's really nice was Google's doodle today for celebrating the new. It's a short animation showing Earth looking through a telescope while the Moon peers over its shoulder. It's the cutest thing you'll see all day.
If Trump where half as smart as he thinks he is, he'd be twice as smart as he really is.
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