Subject: Can someone please explain?
Posted by: Mixamatosis
Date: Jan 21 17
I've read that it's dangerous to mix ammonia and bleach. Variously I've read that it can produce deadly cyanide gas, chlorine gas (which is said to be bad for you) and even explosions.
However swimming pools are kept fit for use with chlorine, and our urine contains ammonia but then we may clean toilets with bleach. Also many cleaning products contain either ammonia or bleach and it would be easy to use them unthinkingly in combination.
How is it that people aren't generally harmed by these dangers when swimming in swimming pools or doing daily cleaning, or are we being harmed at low level and is the harm cumulative?
Posted by: Mixamatosis
Date: Jan 21 17
I've read that it's dangerous to mix ammonia and bleach. Variously I've read that it can produce deadly cyanide gas, chlorine gas (which is said to be bad for you) and even explosions.
However swimming pools are kept fit for use with chlorine, and our urine contains ammonia but then we may clean toilets with bleach. Also many cleaning products contain either ammonia or bleach and it would be easy to use them unthinkingly in combination.
How is it that people aren't generally harmed by these dangers when swimming in swimming pools or doing daily cleaning, or are we being harmed at low level and is the harm cumulative?
526 replies. On page 1 of 27 pages. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27
Mixamatosis 
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P.S. I hope other people will also find this thread a useful space to ask their own questions and seek explanations. Reply #1. Jan 21 17, 5:17 AM |
brm50diboll
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It is all a matter of concentrations. In a swimming pool, the concentrations of chlorine and ammonia are too low to interact the way they do when they are concentrated. Of course, we could all get sidetracked with the "long-term cumulative damage" bugaboo, but people have been swimming in chlorinated pools for over a century, and to the extent this has been studied at all, it is far safer than in natural waters which have much higher concentrations of microorganisms than chlorinated swimming pools do. In the 19th century, death from water-borne illnesses like typhoid fever and cholera was much more common in industrialized countries than today. So I say: Yea chlorine! Reply #2. Feb 03 17, 10:19 PM |
| Mixamatosis
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Thanks for the explanation. Glad I don't have to worry about accidentally producing cyanide gas. Over to anyone else with a science question.... Reply #3. Feb 04 17, 3:01 PM |
daver852
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You can also create a powerful explosive if you mix iodine crystals with ammonia. Reply #4. Feb 04 17, 7:57 PM |
| Mixamatosis
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Aaargh. Something else to be concerned about except that I don't know that I'd ever use iodine crystals in normal daily activities. I don't really know what they are for. Reply #5. Feb 05 17, 5:53 AM |
| Mixamatosis
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I've googled it now. Perhaps the moderators should close down this thread as there could be information on it helpful to those who intend harm. My motivation in creating it was to avoid harm being caused accidentally. What do you think? Reply #6. Feb 05 17, 5:57 AM |
| Mixamatosis
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The other night possible around 5-6 p.m. (but can't be exactly sure) while leaving home in London (facing south west) we saw the moon and to the right of it what appeared to be 2 large bright stars, so close together that at first they appeared to be a plane, but as we watched they did not move. I could not see any other stars though my daughter said she could see some faintly. Having googled now, I believe we were seeing 2 planets. Mars Venus and Uranus are meant to be visible now in that direction. I think it must have been Mars and Venus. I'm not too knowledgable on astronomy. Would anyone be able to confirm that? Reply #7. Feb 05 17, 1:17 PM |
| brm50diboll
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Venus for sure. It is extremely bright in the West after sunset now. Mars can be seen, but is not as striking as Venus. As for Uranus, while technically it can be seen in very dark skies by individuals with sharp vision, I have never seen Uranus with the naked eye (I have seen it with binoculars.) Most of the time when people who don't know much astronomy see what they think is a very bright "star" in the West after sunset (within 3 hours or so after sunset), they are actually looking at Venus. Venus is much brighter than any true star (Sirius is the brightest true star in the night sky and Venus is about ten times as bright as Sirius.) Venus alternates between spending a few months as the "Evening Star" in the West after sunset followed by a few months as the "Morning Star" in the East before sunrise. Venus is currently very obviously in its "Evening Star" manifestation. Reply #8. Feb 05 17, 10:03 PM |
| brm50diboll
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Venus, Mars, and Uranus are all currently located in the constellation Pisces in the West shortly after sunset. Pisces itself is a fairly dim constellation. A complete novice can recognize Venus, but it takes more practice to recognize the stars of Pisces and the interloper Mars. As for Uranus, that requires quite a bit more astronomical sophistication to recognize. I consider myself a serious amateur astronomer. Mars is no problem for me (though most novices can't tell it's Mars, just a star). I have seen Uranus with binoculars, but it is definitely not easy to pick out even with that from the background stars. It requires a good star chart (or app, as I have) to be sure what I'm looking at is actually Uranus. Reply #9. Feb 05 17, 10:25 PM |
| Mixamatosis
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Thanks for that info. What we saw was definitely very bright. I think it must have been Venus but there were definitely 2 bright objects close together. I can only think the other bright object was Mars. I imagine Mars to be brighter or fainter depending on its position and the time of year. I wish I could recognise more constellations. I am a Pisces but would not be able to point it out in the night sky. I'll take more trouble to find out about it and identify it now. The cloud cover is usually heavy in London so the stars are not always easy to see. Reply #10. Feb 06 17, 1:02 AM |
| Mixamatosis
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Having googled it, I see that Pisces looks like a large V with a triangle attached to one arm and a more circular loop attached to the other. I wonder how people decided which stars to link up in the ways they did, to form constellations. Is there any logic to it, or could they have "joined the dots" in other ways? Reply #11. Feb 06 17, 1:10 AM |
| brm50diboll
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Mars varies considerably in brightness depending how close it happens to be to Earth at the time. I could talk about the magnitude scale, but it would require quite a bit of space to properly explain. Let me instead just say that Mars is of fairly medium brightness for it presently. (Magnitude +1.1) This corresponds to the brightness of a star like Betelgeuse in Orion (very roughly). It's easily seen in a dark sky, and not nearly as bright as Venus, but considerably brighter than the nearby faint true stars of Pisces. That, combined with its reddish color, should make Mars easily identifiable in the otherwise faint constellation of Pisces in the western sky after sunset to an experienced observer, (such as me). Just don't confuse it with Venus. Venus is much, much brighter than Mars. Reply #12. Feb 06 17, 1:20 AM |
| brm50diboll
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Different cultures did have different ideas for groupings of stars in the sky. Most of the presently accepted constellations in the Northern Sky date back to the ancient Greeks. But other cultures (examples China, Maya, Polynesia, etc) saw completely different patterns; that is, they linked the dots very differently than the Greeks did and called the patterns they saw by very different names. The constellations of the Southern Sky (not visible from England or most of the US) were named much later by explorers who had gone to the Southern Hemisphere where they could be seen. These Southern constellations were mostly named in the 18th century and frequently were named after the technology of the time (examples: Microscopium, Telescopium, Octans, etc.) Reply #13. Feb 06 17, 1:27 AM |
| brm50diboll
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For any interested novices that may be reading this, planets (as well as the Sun and the Moon) tend to stay within a few degrees of a circle in the sky called "The Ecliptic". The ecliptic passes through the well-known constellations of the Zodiac, of which Pisces is one. But planets (which is a Greek word for "wanderer"), move along the ecliptic (nearabouts anyway) in complicated looping patterns which vary tremendously depending on which planet we are talking about, but the main point is, they move from one zodiac constellation to another at variable rates. So although Venus, Mars, and Uranus are currently within the boundaries of the constellation Pisces, they are interlopers. They are only in Pisces temporarily, and will move on the other zodiac constellations in their own time. The inner planets move faster than the outer ones. Uranus will actually spend several years in Pisces before moving on to Aries. For Venus and Mars, a few months in Pisces before moving on. Reply #14. Feb 06 17, 1:50 AM |
| Mixamatosis
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Very interesting. How many planets have you seen? I remember reading somewhere that the star Betelgeuse is no more, but because the light from it is travelling such a huge distance, there's a great time lag before it disappears from our sight. In the meantime we can still see it. Betelgeuse is my favourite name of all the stars. What a pity it blew up. Reply #15. Feb 06 17, 6:16 AM |
| brm50diboll
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You are incorrect about Betelgeuse. It is still there in Orion. Betelgeuse is a red supergiant nearing the end of its life. It is theoretically possible the star may go supernova in our lives, but very unlikely, given than even supergiants have lifespans in the millions of years. If Betelgeuse were to go supernova, it would be headline news everywhere in the world because, as the nearest red supergiant to us, the supernova explosion would be easily visible in broad daylight! One more time: Betelgeuse has not exploded. It is still a prominent star in Orion, the most famous of all the constellations (though not in the zodiac.) On a clear night, anyone can see Betelgeuse now, because Orion is a winter constellation (in the Northern Hemisphere.) Reply #16. Feb 06 17, 8:10 PM |
| brm50diboll
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I have seen all eight currently recognized planets, though Uranus and Neptune required binoculars and Neptune was extremely tough even with binoculars. The others are all observable with the naked eye, but Mercury is the toughest, because it always stays close to the sun. There are only very brief "windows" a couple of times a year, when Mercury gets far enough away from the sun (as viewed from earth) for it to be visible briefly very low in the West near the horizon after sunset during early dusk. Alternatively, it may be spotted briefly very low in the horizon in the East during late dawn immediately before sunrise a couple of times a year. You need a good star chart and keep up with planet positions to be able to catch Mercury in its short periods where it may be seen. Venus, Mars, Jupiter, and Saturn are all easily seen when they are visible. Reply #17. Feb 06 17, 8:19 PM |
| brm50diboll
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Betelgeuse is only about 640 light years from us. Statistically, it is very unlikely that it exploded in the last 640 years. The Wikipedia article on Betelgeuse states that it could explode at any time in the next 100,000 years. 640 divided into 100,000 is a very small quantity. Betelgeuse is still there. Our understanding of stellar astrophysics is not advanced enough to forecast supernovas very accurately right now. But Betelgeuse isn't even the supergiant felt most likely to supernova soon. The star astronomers feel is even closer to exploding in a supernova than Betelgeuse is Eta Carinae, a southern hemisphere star much farther away and not visible from England or most of the US (it is visible from Hawaii.) Reply #18. Feb 06 17, 8:37 PM |
| daver852
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Positions of the stars are constantly changing, just very slowly. The night sky and the various constellations would have looked a little different to the ancient Greeks than they do to us today. https://www.theatlantic.com/technology/archive/2014/11/the-constellations-wont-always-look-this-way/382721/ Reply #19. Feb 06 17, 8:54 PM |
| brm50diboll
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That is true. But this so-called "proper motion" of the stars is so slow it is not noticeable in a human lifespan, only over thousands of years. There is also the phenomenon of "precession of the equinoxes" which causes the sun's position on the ecliptic to slowly change over thousands of years. One should be extremely, extremely careful about applying astrology to astronomy. In the time of the ancient Greeks, the sun really was in Aries on the day of the spring equinox, hence the term "First point of Aries". But today, the sun is in Pisces on the day of the spring equinox. Roughly speaking, the astrological sign of the sun and the true astronomical position of the sun are off by about one zodiac constellation now due to the precession of the equinoxes over the millennia. Reply #20. Feb 06 17, 9:21 PM |
526 replies. On page 1 of 27 pages. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27
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