After exercising vigorously one can sometimes smell ammonia and it feels like it's coming from within the nose actually. There is no indication that others can smell it when I do (i.e. seems to be internal rather than external). I know I'm not the only one experiencing this, but I was wondering what the physiological processes are that are responsible for that?  Also: is this merely a perceived smell or is there actually ammonia in/on my body after the exercise.
123014
On extended bicycle trips I sometimes slept under a plastic sheet, which helped with mosquitoes on hot nights. But there was a noticeable build-up of ammonia which made this almost impossible for more than an hour or so at a time.   Air is mostly nitrogen $(N_2)$ and there is always water (containing hydrogen) on a humid day. But I wonder about the mechanism for the formation of ammonia under these circumstances? There are (according to Wiki) trace amounts of methane and $H_2$ in the air. But methane and hydrogen (g) are I think pretty stable.   I wonder if the presence of exhaled air (containing $CO_2)$ could be a factor?  Thanks for any ideas.
90396
I understand that newborn's immune system is still weak and crowds/strangers are to be avoided. Knowing this, how soon can I take my newborn outside, for example to take ~1 hours walk in a non-crowded park? Any particular things to pay attention to when doing this?
50556
I hope this is a valid question to ask. I wondered about the different expressions one can use for heavy or unstable breathing. Rather than being heavy breathing from exercising, it's heavy, laboured breathing due to negative emotions.   Would these work ? :   "uneven breath/breathing" "quickening breath"   Is there also an expression or phrasing to implement a "breathing that's growing... [rasp/laboured/winded] ?  Are there other expressions to describe the following statement "her pulse quickened". I assume it depends on context, but does this expression implies a positive source or a negative one ?  In terms of regular breathing, can one qualify someone's breath of "steady", or "quite steady" ?  Essentially, how does one breathe in English ?
100193
I am trying to pickle some mangoes the Indian way. I boiled the jar in hot water, dried it and then added the mixture of spices, salt and mangoes to the jars after the mixture had cooled. I made the mixture in a frying pan to try and remove as much water as I could. After it was cooled, I put it in the jar and heated some mustard oil till it just barely started smoking. I let that cool and poured it over the mango spice mixture.  For the first three days it was fine. On the fourth day, I opened it to test the taste and ended up adding more salt. Now, there seems to be gas forming in the jar. I've noticed it a few times now. When I open the jar, I hear a whooshing noise as air escapes. It's quite a lot, since I opened the container about 3 times in a 10 hour period and each time gas escaped. Has this pickle gone bad? Or is this something that's normal?
106806
There are some fruits* that cause a peculiar (unpleasant) numb sensation in the mouth. An unripe  or a  are two examples that come to mind. I can't describe the feeling any more eloquently so my bet/hope is that you will know what feeling I am talking about.  Is there a word in English that describes the mentioned quality of these fruits and/or the sensation in the mouth?   *I don't know that only fruit can cause it, but I can't think of anything else at the moment.
107580
I have always relied on my sense of smell to determine whether meat (most often chicken) is bad and I thought it was reliable. However, I have just heard that [1] smell is not always reliable, since some of the toxins produced by bacteria won't cause any smell whatsoever and you won't be able to notice that the meat is off until after you've eaten it.   Is this true? If yes, is this true for all meat or only for some? Is there a more reliable way of determining whether meat is still good.  [1] "Heard that" isn't very reliable; so that's why I'm asking the question here. :)
95988
Let's say I'm in a room with some kind of noxious stink, possibly of flatulent nature.  The quickest way to right the world that comes to mind is to open a window.  When I open a window, how do the stank particles leave the room?
95164
Let's say I go to the gym and lift some weights an hour.  During this time my arms will grow due to the "pump" -- the extra blood rushing in to feed the muscles.  For example, I've measured about 2-3 centimeters increase just in the diameter of the upper arm (bicep+tricep).  But where did this blood come from?  Also, if my arms got bigger, since I'm the same weight that means some part of my body must have gotten smaller, right?
61959
Obviously, most beers are carbonated with carbon dioxide, while some stouts/porters are "carbonated" with nitrogen.  I was curious if there has been any notable experimentation with other gasses to "carbonate" beer. If nitrogen can introduce a "creamy" texture to a beer, I would think that other gasses would also be able to introduce their own characteristics on beer. If any of these experiments have done, what characteristics do these other gases impart?  I'm sure cost would be an issue for certain gasses that would prohibit its use in beer, but for purposes of this question, cost is irrelevant.  As an aside, what is the correct term to use, as opposed to "carbonate", for a question of this nature?
53526
People seem to believe that one's consciousness is a "different" consciousness than that of others, but the "same" consciousness as the one that has been in one's body in the past and the one that will be in one's body in the future. How likely is this to be true and why?   Also, I have almost no knowledge about neuroscience, so please refrain from using neuroscience jargon if feasible.
7117
When I'm rotating, I feel centrifugal force. But if I were the only one in the universe and rotating, wouldn't I just kinda be still (since I'm not rotating with respect to anything) or would there just be a force pulling me out? What if there were another person a billion miles away, this should not change anything, right?
55061
How long do you wait before taking corrective action if your fermentation doesn't start?  Are there any other good ways to tell if it's just taking a while to get going?
121611
Kind of a strange question, but say something has spoiled, i.e. smells bad, tastes bad, etc.  Will it actually always make you sick? Like for instance spoiled dressing, let's say it tastes sour, smells nasty and you eat it, will it make you sick?  If so what actually makes you sick? The toxins/bacteria? or it just being unappetizing?  I ask because I tried a TINY bit of ranch and while it tasted mostly fine (it was a bit tangy) it smelled quite tangy but looked fine. I also saw .
8253
When your body burns calories and you lose weight, obviously mass is leaving your body.  In what form does it leave?  In other words, what is the physical process by which the body loses weight when it burns its fuel?    Somebody said it leaves the body in the form of heat but I knew this is wrong, since heat is simply the internal kinetic energy of a lump of matter and doesn't have anything do with mass.  Obviously the chemical reactions going on in the body cause it to produce heat, but this alone won't reduce its mass.
6168
I've read the discussion here about .  I've also read this one: .  But I did not find any word or phrase that describes the reaction someone has when eating a too spicy-hot food. You know, they tend to sweat, catch their breath, and even sometimes shed tears; due to the spiciness of the food.  So my questions:        What do you say to describe the reaction someone has when being excitedly "suffered" by a very spicy-hot food? In Indonesian, we would call it kepedasan.   What do you say when you get that thing [the answer to question 1] with you, other than the list I enclose below:                Oh, spicy!     My God, it's spicy-hot!                      Is that it?
27230
I haven't done this for a very long time. I am following , which conveniently fits perfectly into a little hack-job of containers I already had. (Related: ) @Athanasius' answer to that question led me to what I'm doing with this batch. At this point I feel pretty comfortable with it:    The two containers are identical, and I have a few inches of water in the top container so that it weighs down the cabbage in the lower container. It seems to be working pretty sweet. I'm three days in and it's starting to smell like something is happening. There is a funk in the air.  So far so good.  Now I am dying to stir it...to do something! Everything I have read (including Athanasius' answer) suggests that in a less awesome container I might have to stir, but now I don't necessarily have to do anything but scoop off scum which has yet to appear.  That's killing me.  Is there a reason not to stir? Will stirring offer any benefit?
20142
I  always used to wonder why this happens..   when one stretches a rubberband to nearly it snapping point holding it close to your skin - preferably cheek(helps feel the heat), it emits heat. While releasing the stretched rubberband holding it close to the skin produces a cooling effect on the skin. Can some one explain the physics behind this pls?