Air &Amp: Fill & Download for Free

This is an interesting question. The short answer is fish do not see water. Look at those adorable eyes.The brain tries to filter out vision obstacles like a nose or filter out or constant vision noise like air. Our brains filter air, so anything with similar information, like air, will be filtered. Same with white noise, body noise, and smells. The brain filters this information to save processing power to focus and survive.Seeing air, we can’t use color as reference information for it, so we use refractive indices. Water has a slightly higher refractive index than air, so we can see it.Yet we evolved on land to filter out air taste, smell, noise, and look. Fish and sea creatures evolved the same way.So the answer is no. They do not see, taste, hear or smell water because it is a constant environment noise.Some water creatures took it further to filter out murky waters like this lobster.See these segmented eyes.Scientists were able to use their design to actually develop cameras that can see through fog or smoke for military purposes.Questions like yours make humanity discover new things and developing new technologies. So keep wondering. :)Update: for those asking can fish see air? No they can’t the same way you can’t see things with lower refraction index than air like helium. Air has lower refraction index so the eye can’t see it.

Actually, the answer to this is interesting.And while gravity is most certainly a real thing, the answer to this question is not “because gravity is stronger.”The actual answer is that the vacuum of space does not exert any force on the atmosphere at all. It does not “suck” the air. We associate the word “suck” with “vacuums” but it’s a misnomer. That’s not what vacuums do.Consider an example where we’ve pumped all of the air out of some box and created a vacuum inside of it. Let’s say we’re on Earth, at sea level, and we poke a hole in the box. What will happen?Air will rush into the box and fill it. Okay. But why did it do that? Was it because the vacuum sucked the air into the box? No.What’s actually happening there is that the air pressure around the box is forcing air into the space with no pressure. The air that fills the box is being PUSHED by air pressure into the empty space.Vacuums never “suck” air. What they do is present an empty space and then air pressure forces the air into the vacuum.Air pressure is not uniform throughout the atmosphere. The lower the altitude, the higher the air pressure; thus, as you move higher, the air pressure decreases. In fact, at the upper limits of the atmosphere, the air pressure reduces to basically nil.And since there’s no real air pressure to speak of up there, then there is no force pushing the air into the empty space.Now, this doesn’t mean gravity isn’t at work here. In fact, gravity is the reason we have air pressure in the first place. Gravity pulls on the atmosphere, compressing it, and creating pressure.If we could magically turn off gravity then the atmosphere would be released from that compression and spring away from the Earth.So, at the root of it, gravity is the thing that keeps the atmosphere near the surface. It just isn’t fighting the vacuum of space to do it.

On my first day as a house surgeon in the large Govt. Medical college, I saw something like this in a patient who was on an IV drip.Unseen by the busy nurse, unknown to the consultant, a large air bubble, was moving slowly down the IV line.I knew that it was going to cause a catastrophe. I jumped in and tightly closed the knob, stopping the life- threatening bubble and promptly disconnected the line.As I was trying to bask in the glory of self pride of saving a life on day one of my medical career, my senior house officer coolly came, reviewed the situation and restarted the drip with an “….ohh new kid” look on his face.I learnt the first lesson that despite my mystery stories telling me otherwise, nothing happens if a small amount of air goes into the venous system.But one decade later I learnt that a similar amount of air pushed into the coronary arterial system during an angiogram can cause a catastrophe.