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Here's a good, old-fashioned species ID question for everyone. I am a farm dweller (southeastern United States), and I have been coming across these things in bales of hay from time to time. They are what appear to be very tiny fruit, the largest being maybe 7 or 8 mm in diameter. They don't look ripe to me, but not knowing what they are, I guess that would be a hard call to make. They are yellow (obviously) and full of seeds (hence, fruit). I was brave enough to taste one, and decided I didn't like the taste; decidedly pepper-like, but quite bitter. The skin, though, has a slightly irregular, almost citrus-like texture. Any ideas? Evan ( talk| contribs) 05:08, 17 December 2014 (UTC)
Some people have a very prominent gap between their front teeth. Here is a photo of an example: Michael Strahan: Why I Never Closed the Gap in My Teeth. Is there a name for that (other than simply "gap")? Also, what causes this? Thanks. Joseph A. Spadaro ( talk) 05:17, 17 December 2014 (UTC)
Thanks, all. Joseph A. Spadaro ( talk) 17:00, 19 December 2014 (UTC)
Inspired by the previous question: Is there a technical name for adult teeth that are missing because they never developed? For example, suppose a person simply doesn't have cuspids and never did, is there a technical name for such missing teeth (or perhaps a name for a medical condition associated with having fewer teeth than normal)? Dragons flight ( talk) 05:33, 17 December 2014 (UTC)
Hi, I'm working on a homework question and basically I feel like I've gotten the whole thing but I'd really appreciate someone else to helping me check because I'm not sure if I did it right.
It's a heat engine problem, going from A to B to C Volumes and pressures are as follows A = 7x10^4 Pa, 2.5*10^-2 m^3 B = 3x10^5 Pa, 2.5*10^-2 m^3 C = 3x10^5 Pa, 7.5*10^-2 m^3
I got that the engine has a power output of 57.5 J by finding the area inside the points (just using 1/2 b*h) and an efficiency of 12% by finding the total heat added by Q=dU+Work from A=>B and B=>, but I'm just not sure if I'm doing it right. Can anyone please help me confirm with their steps?
166.137.252.91 ( talk) 05:41, 17 December 2014 (UTC)
I think we're missing some information here. From A to B the pressure goes up and then from B to C the volume goes up. In both steps energy is being added to the gas. But we don't know what kind of gas it is, its mass or its specific heat. 50.43.56.168 ( talk) 08:28, 17 December 2014 (UTC)
I think I'm supposed to assume it's an ideal gas, and the temperature at A is 290K. 67.247.2.127 ( talk) 02:45, 18 December 2014 (UTC)
Your first statement is incorrect. Joules is not a power output. J/s is power and is expressed in Watts (alternatively as horespower). -- DHeyward ( talk) 06:55, 18 December 2014 (UTC)
What do the galaxies in the Local Group orbit around? Whereismylunch ( talk) 07:51, 17 December 2014 (UTC)
But what's at the gravitational centre? — Preceding unsigned comment added by 199.119.235.178 ( talk) 08:58, 17 December 2014 (UTC)
The recent test flight of the Orion spacecraft ended with a splashdown in the Pacific Ocean where is was picked up by the USS Anchorage. How far was the ship from the point where the spacecraft touched down? What was the predicted impact point and/or area? Once the retro rockets have been fired, does the spacecraft have any further control of where it lands? — Preceding unsigned comment added by 50.43.56.168 ( talk) 08:13, 17 December 2014 (UTC)
I read yesterday in a Simon & Schuster mammal field guide from about 1985 that lionesses tend to kill their prey with a single blow to the back, breaking the spinal cord. I'm not naive enough to simply ask how could it be that striking with a paw leaves the prey with fatal damage but no damage to the lioness' paw, but I was just intrigued at everything that needs to go into such a technique. It seems obvious to me that lionesses do not consider their options like a person would, but of all the possibilities and all the alternatives, I find it fascinating that the lioness would consider this means of execution over, say, chomping on the trachea. I see Youtube videos on lionesses attacking buffalo and they seem to try to bit into the ventral neck, but the buffalo resists. What sort of force is required to tear out a trachea, and why would a lioness find that difficult? Is it really more efficient to snap a spinal cord? Thoughts and insights are welcome. Thanks! DRosenbach ( Talk | Contribs) 17:18, 17 December 2014 (UTC)
“ | Cheetah spend several minutes killing prey. Five minutes is common, but 15-25 minutes was not rare, even with small
impala fawns.
Some prey revive from strangulation killing attempts and have to be “strangled” two to three more times before death occured. |
” |
I ran across an interesting story at [8], in which three planes flew close overhead and fine spiderweb-like fibers were then seen sticking to the landscape. I am for now discounting the site's explanation of "geoengineering" entirely, but assuming the truth of their published lab analysis that indicates the presence of aluminum (1020 mg/kg), barium (34.1 mg/kg), and strontium (70.8 mg/kg). These are small but perhaps not negligible amounts, up to 0.1% aluminum in the sample as collected.
To be clear, I have found a fairly persuasive "debunk" of the story at [9]. If we assume that the witnesses were wrong about the association with the planes and the fall of the webs immediately afterward, or if it's just a remarkable coincidence, the webs are explained; if they were contaminated with soil the aluminum is explained; I'm not so sure about the rarer barium and strontium. The test was consistent with spider silk, which would be more impressive if they hadn't first identified it as wheat flour and bacitracin; suffice it to say that some non-metallic matrix containing peptide has to be the major constituent of whatever these fibers are.
But to be contrary, just because the fibers look natural doesn't rule out another explanation, since they might intentionally be camouflaged. My question is whether this data could be explained with some known form of antenna that could be sprayed through a nozzle as a plane flies overhead, land as an intact radio-reflective surface, and then have a signal bounced off it to measure changes to it, i.e. vibrations caused by the speech of nearby persons? (as a wild guess, probably wrong because it also contains titanium, see [10]). Alas, I'm not familiar with this literature. How thick would such a metal fiber actually have to be to be used this way? And is this metal composition actually practical to include in some sort of polymer "spider silk" that can be sprayed from a plane?
I'd also welcome any other possible explanations. Wnt ( talk) 21:51, 17 December 2014 (UTC)
I came across something that sounds vaguely similar. Google "Huntsville weather anomaly". Here's one site: http://valleywx.com/2013/06/04/mystery-blob-over-west-huntsville/ — Preceding unsigned comment added by 50.43.56.168 ( talk) 01:35, 18 December 2014 (UTC)
Science desk | ||
---|---|---|
< December 16 | << Nov | December | Jan >> | December 18 > |
Welcome to the Wikipedia Science Reference Desk Archives |
---|
The page you are currently viewing is an archive page. While you can leave answers for any questions shown below, please ask new questions on one of the current reference desk pages. |
Here's a good, old-fashioned species ID question for everyone. I am a farm dweller (southeastern United States), and I have been coming across these things in bales of hay from time to time. They are what appear to be very tiny fruit, the largest being maybe 7 or 8 mm in diameter. They don't look ripe to me, but not knowing what they are, I guess that would be a hard call to make. They are yellow (obviously) and full of seeds (hence, fruit). I was brave enough to taste one, and decided I didn't like the taste; decidedly pepper-like, but quite bitter. The skin, though, has a slightly irregular, almost citrus-like texture. Any ideas? Evan ( talk| contribs) 05:08, 17 December 2014 (UTC)
Some people have a very prominent gap between their front teeth. Here is a photo of an example: Michael Strahan: Why I Never Closed the Gap in My Teeth. Is there a name for that (other than simply "gap")? Also, what causes this? Thanks. Joseph A. Spadaro ( talk) 05:17, 17 December 2014 (UTC)
Thanks, all. Joseph A. Spadaro ( talk) 17:00, 19 December 2014 (UTC)
Inspired by the previous question: Is there a technical name for adult teeth that are missing because they never developed? For example, suppose a person simply doesn't have cuspids and never did, is there a technical name for such missing teeth (or perhaps a name for a medical condition associated with having fewer teeth than normal)? Dragons flight ( talk) 05:33, 17 December 2014 (UTC)
Hi, I'm working on a homework question and basically I feel like I've gotten the whole thing but I'd really appreciate someone else to helping me check because I'm not sure if I did it right.
It's a heat engine problem, going from A to B to C Volumes and pressures are as follows A = 7x10^4 Pa, 2.5*10^-2 m^3 B = 3x10^5 Pa, 2.5*10^-2 m^3 C = 3x10^5 Pa, 7.5*10^-2 m^3
I got that the engine has a power output of 57.5 J by finding the area inside the points (just using 1/2 b*h) and an efficiency of 12% by finding the total heat added by Q=dU+Work from A=>B and B=>, but I'm just not sure if I'm doing it right. Can anyone please help me confirm with their steps?
166.137.252.91 ( talk) 05:41, 17 December 2014 (UTC)
I think we're missing some information here. From A to B the pressure goes up and then from B to C the volume goes up. In both steps energy is being added to the gas. But we don't know what kind of gas it is, its mass or its specific heat. 50.43.56.168 ( talk) 08:28, 17 December 2014 (UTC)
I think I'm supposed to assume it's an ideal gas, and the temperature at A is 290K. 67.247.2.127 ( talk) 02:45, 18 December 2014 (UTC)
Your first statement is incorrect. Joules is not a power output. J/s is power and is expressed in Watts (alternatively as horespower). -- DHeyward ( talk) 06:55, 18 December 2014 (UTC)
What do the galaxies in the Local Group orbit around? Whereismylunch ( talk) 07:51, 17 December 2014 (UTC)
But what's at the gravitational centre? — Preceding unsigned comment added by 199.119.235.178 ( talk) 08:58, 17 December 2014 (UTC)
The recent test flight of the Orion spacecraft ended with a splashdown in the Pacific Ocean where is was picked up by the USS Anchorage. How far was the ship from the point where the spacecraft touched down? What was the predicted impact point and/or area? Once the retro rockets have been fired, does the spacecraft have any further control of where it lands? — Preceding unsigned comment added by 50.43.56.168 ( talk) 08:13, 17 December 2014 (UTC)
I read yesterday in a Simon & Schuster mammal field guide from about 1985 that lionesses tend to kill their prey with a single blow to the back, breaking the spinal cord. I'm not naive enough to simply ask how could it be that striking with a paw leaves the prey with fatal damage but no damage to the lioness' paw, but I was just intrigued at everything that needs to go into such a technique. It seems obvious to me that lionesses do not consider their options like a person would, but of all the possibilities and all the alternatives, I find it fascinating that the lioness would consider this means of execution over, say, chomping on the trachea. I see Youtube videos on lionesses attacking buffalo and they seem to try to bit into the ventral neck, but the buffalo resists. What sort of force is required to tear out a trachea, and why would a lioness find that difficult? Is it really more efficient to snap a spinal cord? Thoughts and insights are welcome. Thanks! DRosenbach ( Talk | Contribs) 17:18, 17 December 2014 (UTC)
“ | Cheetah spend several minutes killing prey. Five minutes is common, but 15-25 minutes was not rare, even with small
impala fawns.
Some prey revive from strangulation killing attempts and have to be “strangled” two to three more times before death occured. |
” |
I ran across an interesting story at [8], in which three planes flew close overhead and fine spiderweb-like fibers were then seen sticking to the landscape. I am for now discounting the site's explanation of "geoengineering" entirely, but assuming the truth of their published lab analysis that indicates the presence of aluminum (1020 mg/kg), barium (34.1 mg/kg), and strontium (70.8 mg/kg). These are small but perhaps not negligible amounts, up to 0.1% aluminum in the sample as collected.
To be clear, I have found a fairly persuasive "debunk" of the story at [9]. If we assume that the witnesses were wrong about the association with the planes and the fall of the webs immediately afterward, or if it's just a remarkable coincidence, the webs are explained; if they were contaminated with soil the aluminum is explained; I'm not so sure about the rarer barium and strontium. The test was consistent with spider silk, which would be more impressive if they hadn't first identified it as wheat flour and bacitracin; suffice it to say that some non-metallic matrix containing peptide has to be the major constituent of whatever these fibers are.
But to be contrary, just because the fibers look natural doesn't rule out another explanation, since they might intentionally be camouflaged. My question is whether this data could be explained with some known form of antenna that could be sprayed through a nozzle as a plane flies overhead, land as an intact radio-reflective surface, and then have a signal bounced off it to measure changes to it, i.e. vibrations caused by the speech of nearby persons? (as a wild guess, probably wrong because it also contains titanium, see [10]). Alas, I'm not familiar with this literature. How thick would such a metal fiber actually have to be to be used this way? And is this metal composition actually practical to include in some sort of polymer "spider silk" that can be sprayed from a plane?
I'd also welcome any other possible explanations. Wnt ( talk) 21:51, 17 December 2014 (UTC)
I came across something that sounds vaguely similar. Google "Huntsville weather anomaly". Here's one site: http://valleywx.com/2013/06/04/mystery-blob-over-west-huntsville/ — Preceding unsigned comment added by 50.43.56.168 ( talk) 01:35, 18 December 2014 (UTC)