Score
Title
82
AskScience Panel of Scientists XVIII
263
AskScience AMA Series: "I am Rhett Allain, physicist and technical consultant on Mythbusters and MacGyver. Ask me about the physics of pretty much anything!
393
Can dogs observe and recognize aging in adult humans? Do they differentiate between young adult, middle-aged and elderly humans?
10968
When does a mushroom die? When it's picked? When it's packaged? Refrigerated? Sliced? Digested?
30
Is it possible to transform martian soil into fertile soil through bacteria and fungi?
9
Do cats purr voluntarily or unvoluntarily?
12
What is the most amount of electrons forcibly added to an atom?
9
Why does the taste of tap water vary between locations?
51
Why do things like saliva or melted cheese pull into strings when you try to separate them?
3
Are seatbelt/phone detection cameras a real thing? And if so, how do they work?
26
I think I understand the difference between aleph-null and aleph-one as countable and uncountable infinities, but what is aleph-two?
10
If the vaporization point of water can be changed by increasing pressure, is the freezing point also affected by pressure?
7
Do any of the stars we can observe with tbe naked eye at night have planets orbiting them?
5743
Does a Mayfly, which only lives a day, evolve fast than a human?
6
The failed recovery of the Falcon Heavy's central core was attributed to the booster running out of TEA-TEB. How does this happen if the amount of fluid needed to ignite the engine, and the number of ignitions required is known beforehand?
5
How do we know what an asteroid is made of?
5
How do developers of Nuclear Weapons either keep (or protect themselves from) radioactive materials like Plutonium-239 from potentially ‘leaking’ out particles? Are there any methods to contain these particles from escaping the material so they won’t hurt biological matter near the material?
7
How does a "loop sensor" in a street work?
4
How far can the human eye see?
2
Could a spacecraft under constant acceleration ever reach near-lightspeed?
5
I've heard that catfish have ring shaped pupils, however this rather surprising adaptation is only ever mentioned in passing. Can anyone provide more information on this?
5
Why are the late derivatives of position so weirdly named?
6
We often see water used as a neutron moderator in fission reactors due to its high Hydrogen content. Would gaseous Hydrogen be a more effective neutron moderator?
3
Could a neutrino interact with a water molecule in my eye and release a photon that I could "see"?
0
Is the threshold frequency for alloys based on the elements in the alloy, or is it a different factor in the photoelectric effect?
23
Are mitochondria significantly different in different species?
12
When a Li-ion battery is first manufactured, is it already charged? If so, how much and why that amount?
1
How do power outages cause transient voltage spikes?
1
How did scientists choose the elements and method by which to create an atomic bomb?
0
What does hacking usually entail? How much of it is like the glamorous stuff we see on tv and how much is just calling and asking for a password?
13
If the four dimensions of space and time are intertwined, why can we not rotate an object into "time" the same way we can rotate an object in 3D space?
132
As a snake grows in length, does it grow additional ribs and vertebrae, or do they have a set number?
4
If an event happens an average of every x years, and it is been >x years since it last happened, are we more likely to experience the event? If so, can this likelihood be predicted?
0
Will checkpoint inhibitors (PD1/PD-L1, CTLA4) cause the host immune system to generate neutralizing antibodies?
6
Why does halorhodopsin only activate when exposed to yellow light and channelrhodopsin with blue light?
5
At an atomic level, what makes a material better at compression or tension?
30
Why isn't Boron created through normal stellar nucleosynthesis (i.e. nuclear fusion in stars)?
1
Are there any approximations for masses of the various continents of Earth?
44
What is special about sunlight versus artificial light that plants need it?
4
Do male species having lower life expectancy than female also occur in other animal species than human?
14
How much complexity can nuclear pasta phases in neutron stars support? Could one potentially have strong-force-based life in a neutron star?
29
Do other animals have 'accents' like humans do?
1828 Madenmann If you boil water, you'll kill most pathogens living in it. Dissolved chemicals or particulates will remain, so if you boil brown water it'll still be brown. If whatever is making the water brown happens to be a toxin drinking the boiled water is still inadvisable. However, you can use boiling the water to clean it. Catch the steam, let it condense and have some clean water. We don't do that generally because it's a rather arduous process and it consumes a lot of energy.
10282 organiker Boiling water doesn't "clean" it. It does, however, kill certain harmful bacteria, which results in water that is safer to ingest.
1415 audiyon No, boiling water only kills living pathogens that can cause diseases. Anything dissolved or suspended in the water, eg. micro-plastics, salt, lead, bleach, will not be removed and will be left behind in a higher concentration after boiling. Water has to be **distilled** for it to be cleaned of other contaminants. See also: [Boiling water for potability](https://en.wikipedia.org/wiki/Boiling#For_making_water_potable) [Distillation](https://en.wikipedia.org/wiki/Distillation)
42 UEMcGill In Pharmaceutical processing there's steam, and *sterile steam*. The two are not synonymous. You may have a processing system that is sanitized, generally free of microbial contamination and expected not to encourage growth to a reasonable limit. Things like shampoo, and lotion are made under sanitary conditions. Food is processed under a sanitary standard also. However, take that steam up to 130C and filter at .2 micron to remove solids and now you have *Sterile Steam*. This is generally assumed to be statistically free of pathogens, although there's a large and ugly formula with exponents to predict just how free something is. You can actually filter something to sterility also, and often this is the prefered method in pharmaceuticals. You may have a material that is heat sensitive, or not easily heat treated. You filter it through a 0.2 micron filter and it removes viruses, bacteria, and solid contaminants. So if your goal is to clean water, the easiest way is to filter it. This will take suspended contaminants out. If your goal is to sterilize it, you need to heat it to 130C for at least 23 minutes and for good measure filter it (0.2 micron)before you heat it. Purifying it is a different matter because different chemistry takes different steps. Things like RO and Ionic bed treatment will do most of it. But "pure" is a mater of specifying it also. There's a diffrence between 99.9% pure and 99.999%.
94 MadScienceDreams To be clear, boiling water doesn't clean it: it kills many disease causing bacteria. Their dead bacteria bodies are still in the water. In fact, a large number of bacteria survive the heat just fine. Some "sporify" - basically go dormant until conditions don't suck as bad. Any other contaminants will still be in the water. Heck, you'll probably add some from whatever container you used to boil the water. There are some really fancy filters that can filter things down to the molecular scale. And of course, there is distilling (turning the water to vapor and then condensing it back to water). Neither of these processes will give you 100 percent pure water though.
18 Iwantmyflag Boiling water will kill most bacteria, viruses, fungi and protozoa - but not all; Bacillus cereus is often found in dry rice but only in low concentrations, safe to consume. Cooking doesn't destroy it so once the rice is cooked it will start multiplying in the now wet warm rice. Boiling (in) water will destroy **some** toxins created for example by plants or bacteria but often it will **not**; Solanin found in potatoes that have been exposed to sunlight would be one example. (Many) Mycotoxins are another. Boiling will not remove heavy metals like Cadmium, Arsenic or Lead, industrial polutants like oil or microplastic, dioxins (thankfully not commonly found in water) or Trihalomethanes.
1829 0 Madenmann If you boil water, you'll kill most pathogens living in it. Dissolved chemicals or particulates will remain, so if you boil brown water it'll still be brown. If whatever is making the water brown happens to be a toxin drinking the boiled water is still inadvisable. However, you can use boiling the water to clean it. Catch the steam, let it condense and have some clean water. We don't do that generally because it's a rather arduous process and it consumes a lot of energy.
10284 0 organiker Boiling water doesn't "clean" it. It does, however, kill certain harmful bacteria, which results in water that is safer to ingest.
1421 0 audiyon No, boiling water only kills living pathogens that can cause diseases. Anything dissolved or suspended in the water, eg. micro-plastics, salt, lead, bleach, will not be removed and will be left behind in a higher concentration after boiling. Water has to be **distilled** for it to be cleaned of other contaminants. See also: [Boiling water for potability](https://en.wikipedia.org/wiki/Boiling#For_making_water_potable) [Distillation](https://en.wikipedia.org/wiki/Distillation)
39 0 UEMcGill In Pharmaceutical processing there's steam, and *sterile steam*. The two are not synonymous. You may have a processing system that is sanitized, generally free of microbial contamination and expected not to encourage growth to a reasonable limit. Things like shampoo, and lotion are made under sanitary conditions. Food is processed under a sanitary standard also. However, take that steam up to 130C and filter at .2 micron to remove solids and now you have *Sterile Steam*. This is generally assumed to be statistically free of pathogens, although there's a large and ugly formula with exponents to predict just how free something is. You can actually filter something to sterility also, and often this is the prefered method in pharmaceuticals. You may have a material that is heat sensitive, or not easily heat treated. You filter it through a 0.2 micron filter and it removes viruses, bacteria, and solid contaminants. So if your goal is to clean water, the easiest way is to filter it. This will take suspended contaminants out. If your goal is to sterilize it, you need to heat it to 130C for at least 23 minutes and for good measure filter it (0.2 micron)before you heat it. Purifying it is a different matter because different chemistry takes different steps. Things like RO and Ionic bed treatment will do most of it. But "pure" is a mater of specifying it also. There's a diffrence between 99.9% pure and 99.999%.
98 0 MadScienceDreams To be clear, boiling water doesn't clean it: it kills many disease causing bacteria. Their dead bacteria bodies are still in the water. In fact, a large number of bacteria survive the heat just fine. Some "sporify" - basically go dormant until conditions don't suck as bad. Any other contaminants will still be in the water. Heck, you'll probably add some from whatever container you used to boil the water. There are some really fancy filters that can filter things down to the molecular scale. And of course, there is distilling (turning the water to vapor and then condensing it back to water). Neither of these processes will give you 100 percent pure water though.
17 0 Iwantmyflag Boiling water will kill most bacteria, viruses, fungi and protozoa - but not all; Bacillus cereus is often found in dry rice but only in low concentrations, safe to consume. Cooking doesn't destroy it so once the rice is cooked it will start multiplying in the now wet warm rice. Boiling (in) water will destroy **some** toxins created for example by plants or bacteria but often it will **not**; Solanin found in potatoes that have been exposed to sunlight would be one example. (Many) Mycotoxins are another. Boiling will not remove heavy metals like Cadmium, Arsenic or Lead, industrial polutants like oil or microplastic, dioxins (thankfully not commonly found in water) or Trihalomethanes.