Why Do Things Look Blurry Underwater?
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- Опубліковано 11 жов 2024
- If you’ve been brave enough to open your eyes underwater, you might have noticed that everything is blurry. But fish have no trouble finding their way beneath the waves. So why can’t we see as clearly below as we do above?
Hosted by: Rose Bear Don't Walk
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So how about animals like penguins who need to be able to see both under and over water?
Evolution Penguins have evolved a flattened cornea which refracts light less strongly than ours and strong eye muscles that can change the shape of the lens allowing for sharper vision underwater. These adaptations allow focus in air and in water.
There are also many animals that have an extra transparent eyelid that does the same job as goggles.
They see over water whit one eye and under water whit the other one
@@marcobistagnino8713 ...here I was thinking they were winking.
@@marcobistagnino8713 This guy is right
"Our vision depends on light bending." I'm more of a water bender, myself.
People call it 'being overweight', I call it 'involuntary gravitational lensing'.
I couldn't think of anything else but Avatar while watching this video lol
How about "air bender" ? I'm actually an elbow bender, and I exercise by doing 12oz. Curls.
@@NuclearTopSpot AHHH, no wonder why you get all the girls
@@jimbrewer498 I'm a knee bender.
Eyes underwater: “I can’t see anything!”
Ears: “Hold my beer”
My ears suck at seeing, no matter where I am.
@@qwertyferix you need to put goggles over them
@@DenkyManner I heard that if you put goggles over your ears while you're diving you'll hear the ocean.
@@cambrown5633 Fun fact, if you cup your hands over your ears.
@@andrewzhao444 Huh. You're right, that worked! Crazy...
So almost everyone in Avatar: The Last Airbender is a bender. They're all lightbenders! except for Toph, but she doesn't need it.
So Sokka twice a bender then.
*-Toph proceeds to do the John Cena "U Can't See Me" hand gesture-*
@@chikiwiki64 ååååååååååååååååååååååååå
She bends vibrations
she can metalbend thats badass enough
I wear glasses and never thought about how other people are seeing underwater... somehow strange because I can see the same underwater as on land
You get use to it, the human brain tries to compensate
Are you far sighted?
I naturally close my eyes underwater. So I don’t know😅
You can buy correction swimming goggles, they aren't too expensive and you see in them properly in an out of water (because the outer side is flat). Just make sure you try the lenses on in the shop rather than buy them based on your numerical values, as they are at a diffferent distance from the eye than normal glasses so need to have different optical power- mine need to be 1 to 2 diopters stronger to work properly.
Tell me 'bout it...
As a kid it was big yellow patch (sandy beach), blue patch (ocean) every time I went to the beach. ; )~
I've since got excellent diving goggles with high prescription lenses - minus 8, I think. My eyes are extremely short-sighted & worse than that (Left: -9.5, Right: -9.0), but it's close enough for underwater.
Now please do a follow up on how archer fish manage to so accurately hit their above water prey despite being under water.
The archer fish never shares its secrets
Possibly the same way human spearfishers do: adjust their aim to account for the refraction.
It's probably less of an intentional correction than for humans, but still plausible 🤷
Biological bifocal lenses?
@@1MarkKeller Yup. It's literally a bifocal lens, what's the top half of the lens refracting for vision in air and the bottom half refracting for vision and water.
Edit: This is outdated mythology. See my reply below.
And I'm wrong. But I'm leaving the first reply up, because this is something that has been perpetuated. Wrongly, as it turns out.
This is what comes of getting your biology knowledge from your kids 20-year-old outdated earth science books. Presumably my grandkids textbooks are better. I hope. It turns out there's some voodoo going on in the retina, and the fish rotate their eyes while still below the surface of the water to line up their shot by putting the image of their target on a special area of the retina. There are some highjinx going on with the pigments in that area of the retina, with opsins (photosensitive pigments) that are often associated with color vision, but they're not sure that they're actually being used for color vision so much as they are to refine the image of their target.
Two lessons here. Double check everything, and remember that somewhere your kids textbooks were selected, vetted and approved by a school board. And as Mark Twain said, "First God made idiots. That was for practice. Then he created school boards."
So what I'm learning from this is that Humans (and other terrestrial tetrapods) are Air Benders, while fish are Water Benders.
Omg THANK YOU for giving me an actual answer to a question I’ve had my whole life
1:15
Your animator is shining the light right where the optic nerve connects, which happens to be a blind spot.
I've always been very short sighted, so my problem was more finding my way back to where I left my glasses, but, in the sea, I found things were less blury under the water, and for a brief time, while my eyes were wet, on surfacing.
I always enjoy episodes more once I hear Rose's voice - calming and informative and interesting is a win!
I like this new host, Rose!
I’m really digging all these amazing earrings!! Also great video!
As a myope i never associated water with blurry vision as i see much better under water 😅
Was thinking the same thing lol, underwater is the only place things aren't really that blurry for me (without glasses)
#metoo
OMG! I can't believe that there are people who don't know this! A 6 year old child can observe the "straw in a half glass of water" phenomenon and a first grade teacher can explain it to them in a comprehensive way to them!
@1:19 To bad it lands on the blind spot in this animation....
I know! I was trying to figure out what they actually meant. The image lands over most of the back of your eye, and that little hole is actually where all the signals travel through to physically travel to your brain.
Oh crap
Then for the in-water case at 1:55, instead of showing the beam not focusing down to a point, they applied a blur to the entire beam.
👍🏻😄🍻😷🦠
@@kindlin And because all nerves and blood vessels enter and exit the eye at that point, there is no more place for photosensitive cells. It is truly a blind spot.
Thanks for the great video. And l love the new host Rose Bear Don't Walk! Good job Rose keep up the good work.
But what about animals that both swim and walk, like penguins and seals? Do they see well in air or underwater?
Your lens can bend just a little bit to help your eyes focus on things at different distances or with more detail. That's why you can get eye strain from reading a book or using your phone for too long, the muscles that bend your lens to read the small text get sore.
In animals that need to see in both air and water, the muscles that bend their lenses are stronger, and the lens itself is more flexible! I think they might also have a cornea more like a fish, so it doesn't bend much. They only rely on bending the lens to focus properly without needing the cornea to bend the light first.
@@7337blackwolf Awesome! I had the same question, glad someone answered it before I got here--thanks!
I can "flex" something in my eyes and see perfectly underwater, and as much as I would like to have a unique power... I know Im not the only one who can. What I dont understand is how can there be so many people who dont know they can do it too...
How would you even go about describing how to "flex" something in your eye? That's the first hurdle.
O my goodness! Rose bear 😍😍😍
All about species that live and water and on land like amphibians. They use their eyes for both mediums
So why didn't that first fish to venture onto land just go "Damn, everything's blurry as heck up here. Imma stay in the water!"?
a few of them prolly did just that. until a few didnt and one lived on.
Can't make pizza underwater!
The first million or so fishes who ventured out on land did. But then came a fish who had very bad eyesight underwater. He had always been bullied in school. And when he accidentally got stranded because with his blurred vision he couldn't read the warning signs not to go too near to the beach, he was surprised how beautiful and sharp everything looked.
Apparently the first fish on land evolved from a fish that had previously evolved to have eyes that could see in air better, to capitalize on being able to spot land dwelling bugs. So basically it evolved eyes to see in air before it came onto land.
Found the answer on this video ua-cam.com/video/I19usgWHJLc/v-deo.html.
What's crazy is that some people, who learn how to do it early enough, can see under water clearly by having their pupils shrink, acting more like a pinhole camera than a traditional vision arrangement.
Another crazy thing: Both cephalopods and whales have evolved spherical lenses to have clearer vision in water.
Me: Omg it's pretty obvious why
Me: **Watches video anyway.**
same.
Me too but Didn't watch just came to the comments to see stupid comments and try to educate.
@@rustzz8 I thought maybe it was a completely different reason or multiple reasons I was unaware of. I never assume I know everything about anything. Even something as small as this
I find it weird that people would be worried about blurry vision while underwater. Shouldn't your first thought be "OMG! I can't breathe!"
Not if you know how to swim
Or... OMG! Why is that big fin following me?
My brain literally went, because there’s a film on your eye?!
Mine went “because my glasses are off” 🤦🏻♀️😂
You guys should be Scientists.
@@AJ-xm4xc lmao
I think I just fell in love
I did too man
Honestly, every time you said "bending" I thought of Avatar the Last Airbender and had some wild mental images.
Now with lasers!
pew pew ... pew pew ... not my cabbages!!!
Just imagine how insane light bending would be!
*me only swims with glasses* What are you talking about? xD
Lmao this Is a wasted video. I feel like a 5 year old could figure out why shits blurry under water
@@BurgerurgerFPV Are you telling me that 5 year olds should not get to watch educational UA-cam videos?
@@Cythil next video should be, “ why is it so blurry when on fire. I wonder if they could figure that one out?
have you ever had a bad, cheap pair of goggles tho?
@@BurgerurgerFPV pretty sure barely any five year old has bothered to read about temperature differences in air causing visual distortions or light refraction and refractive index, let alone know the concept of how air even has particles in it that move around more when you heat them up and how different materials even refract light
you're basically saying sci show should just gatekeep by only catering to more educated individuals instead of basically anyone, even kids, who love science
Please do a video on the evolution of cacti and where they came from
That was really really interesting. Thanks!
"light bending"
Me: SO THERE'S A FIFTH ELEMENT
Edit: I just want to clarify that this is an Avatar the last airbender reference. Also I got 69 likes as of now
? Huh? I mean yeah, Boron I think..? Is this a meme?
Air, earth, water, fire...and light
You mean the movie?
N-na-nani?
@@gregoryfenn1462 it was an avatar the last airbender reference
Fish don't need glasses to see underwater.
Bubble Bass: Am I a joke to you?
Rose: "our vision depens on light bending"
Brain: completely loses focus ans tart thinking baut Avatar.
Nice to meet you, Ms. Bear Don't Walk! Good show.
I love this channel
I've always worn contact lenses when I swim so I'm good in & out of the water as long as I have goggles. What's weird is that in recent years I got in the habit of swimming early morning laps and started to not bother with the contact lenses. I can barely recognize people without contact lenses/glasses unless they are really close up. I notice that I can now see clearly under water with or without contact lenses when I'm wearing ordinary (non-prescription) swim goggles. It's always clear under water, but when my head is out: blurry vision unless my contacts are in! It never used to be this way.
you must be near sighted. Near sighted folks can see more clearly underwater!
@@nataliearciniega2103 Yup, I am.
So in theory, could people with just the right amount of short-sightedness see clearly under water?
I dunno how short sighted one would have to be, I'm a bit short sighted and I used lenses in my diving mask, unlike eye glasses, the focusing power of mask lenses can only be increased by increments of .5, while eye glasses can be increased by .25, when I ordered my mask, I rounded down, and it worked like a charm, since then I had to increase my eye glasses, but the mask remained the same and still works
Can confirm as i can see underwater just fine, but im shortsighted as hell and need stuff to be right infront my eye unless i got glasses
@@osiristhefallen8554 very interesting! Mind sharing how many diopters you have?
@@zeawoas haha, i would but im not sure offhand. I just know when i swim i can see better through water than air, pretty useless to me but hey its cool! My last eye doctor said my retinas are so destroyed that theyre football shaped. Ill ask my next visit and let you know
@@osiristhefallen8554 oh wow, sorry to hear. Hopefully they don't get any worse! Thanks for the reply and all the best anyway!
Such a pretty top and a great episode Rose!
I mean this without any irony or bitterness; this host has a kick-ass name
This is actually really interesting
I like this narrator...👍
Rose Bear Don't Walk has become an incredible host, I love every video she does.
So basically, the fish out of water is going is going "I can't see... I can't see..." While being asphyxiated.
Yet again, a question I didn't realize that I had. Thanks as always SciShow!
There is a research from Anna Gislén on Moken children in Thailand. 2003. Children quickly adapt their vision to see clearly underwater. Interesting adaptation. I dont know is there more recebt research on the subject.
Ohhhh nice. Diversion. Mind. Politicized. Bless you alllll! I Love Science!!!
Fish first came onto land to find their glasses.
Fantastic new presenter (new to me anyway, must go look up previous videos). Very effective and clear communicator, great speaker, very natural conversational style.
This was actually pretty interesting!
loved the presentation
Good video! Midnight thoughts I've wondered about.
I also noticed that some off-the-shelf swim goggles tend to blur my vision quite badly, specifically those with curved lenses. Goggles with flat lenses don’t have this effect to my eyes. On the other hand, I think peripheral vision is far better with the curved lenses, while flat ones seem to have a slight magnifying effect, and a bit less peripheral vision as a result? Has anyone else noticed this?
Evolution is amazing!
What's funny is that my eyes are terrible, and I have a particularly severe astigmatism in my right eye, but I actually see more clearly underwater without correction that I do normally without my glasses.
I would get blurry vision underwater anyway because my contact lenses would probably come off. :-)
So good! And wow, sweet fashion. Much love.
If we need glasses with some air to see underwater. Do fish need glasses with water in them to see outside the sea? 🤣
Also, now i'm thinking of fish that wear glasses.. thanks for that imagine xD
In a swimming pool I can see perfectly fine if it's clean. It just takes focusing differently than in air. Though you can't see what's above at all. Personallu I find seeing in water without goggles easier than with them. Though don't do that with unsanitized water like a river or lake.
What about animals that go between water and air a lot, like seals or diving birds? Is it just a matter of each relevant species having a harder time seeing in one of the two areas, or do some animals have a way to focus light effectively in both environments?
I have severe astigmatism, like almost egg shape. I see better underwater without glasses than I do in open air without glasses
Born to Scuba dive!
It is possible to make an eye that works properly in air and water, only the outer surface of it has to be flat, so the transition between the internal medium and external medium doesn't act as a lens. This is what happens with swimming goggles and waterproof camera enclosures. I wonder if there is an animal that has evolved eyes that have the outside of their lens flat or have some sort of flat scale over it to enable correct vision in air and water.
I wonder if the pressure from the water pressing on the eyes also defocuses them even further or if its so small an affect that its unnoticeable?
Ah, I see now, that's cleared things up, they were a bit of a blur... :P
Haaach I love science so much!!
I guess that's why i have it as a job and as a UA-cam channel!!
Thanks for this great video this is really well explained
My eyes watering while watching this
SciShow: The human eye is Amazing!
Cheddar:
How the human eye is an evolutionary design failure.........just like you.
Upcoming Cheddar video: Why you're a design disaster and you always will be.
Yeah well what's next? our existance itself to be a failiure? lol.
i know this is not related to the subject of this video at all, but i really love rose as a host. her speech pattern us fun to listen to and her fashion sense is awesome. keeps me engaged in what i'm hearing and also giving me a fashion show. glad she's joined the team.
PERFECT, now i need to learn a bit more about astigmatism in lobsters
TY 😃
I found out as a child that if I held my head face down in water and blew bubbles, every so often a bubble would land directly on my eyeball and for a moment I could see with perfect clarity as if I were wearing goggles. Now I know why!
IIrc it's thought that fish adapted to catching insects flying above the water surface before they adapted to go out of the water. People think this because there are fossils of fish in areas with shallow water with their eyes on top of their heads from before their lobed fins adapted to being more limblike.
She has the perfect delivery.
So fish need goggles filled with water to see sharp on land, gotcha.
The Four-eyed fish (genus Anableps) lives at the surface and can see clearly through both air and water. It really only has two eyes, but each eye is divided.
I never noticed, because I always wear swimming goggles. LOL
Lightbending slice! Yip yip!
My vision underwater (with goggles) is better than my vision out of water (without glasses).
Please make a video on intermittent fasting and one meal a day diet
As a nearsighted (my eyes have a too strong focusing power) and astigmatic (my cornea is not symmetrical) human I see way better underwater than in air (without correction and for far objects -far being more than 10 cm)
What about water pressure pushing on the eyeball changing the focal length of your eyeball?
there are those mudskippers that swim at the surface of the water, and half thier eyball is above and the other is below the water line, and their eyes are different to account for each.
2:21 nice
How would you explain the vision of animals who can live on both outside and inside the water?
I'm starting to develop feelings for Rose Bear. And I think there's a scientific reason for that.
😜
Brains and beauty
She is very, _very_ far left, so I hope you ain't a conservative.
want to think about something interesting? So lasik and other laser corrective surgeries reshape the cornea to alter its focusing power. I had severely nearsighted eyes before Lasik. After Lasik I can see just fine... until I get in the water. My vision is sooooo messed up underwater.
So being myopic is just a free trial of how our distant ancestors see the world?
You should have mentioned that dolphins see blurry underwater just like us because their eyes haven't evolved yet to see well underwater or they just don't need to because echolocation.
I saw the thumbnail and inmediatly thought "the SciShow iceberg"
A friend of mine was genuinely surprised when I asked why he didn't bother with a mask underwater to get rid of the blurring. His answer was basically "what blurring?" It seems he had never realised that everyone else can't see clearly underwater. Any answer to that one?
near sighted people can see more clearly underwater bc normally nearsightedness is caused by too much bending of light which makes the focal point before the retina. This might be because your eye is too long, the cornea too curvy or the eye's lens is too large. But if you go underwater, you'll become slightly more farsighted than your usual, so this might make you be able to see better than a normal-sighted person.
Goggles make nearsighted people see perfectly, blurry in air but clear with goggles
If you barbecue whole fish you can often see their little, hard, round lenses pop out of their eyes. The heat makes them cloudy looking though.
Humans can learn to see "better" underwater... This is evident in tribes that do much underwater scavenging or hunting - the pupils contract underwater to provide a slightly darker, albeit somewhat sharper image.
Rose Bear Don't Walk, nice job! love it.
I like your shirt! Good job hosting too!
Soo, if i want to let my fish see clearly outside the water, i need to fill his goggles with water.
Got it! Learn something every day!
Cool, cool... what about aquatic mammals that spend a lot of time in the surface? Like otters or seals and such
So amphibious animals just have really elaborate rye muscles?
as someone who wears goggles, i might never have known other people experienced this at all. I just find my eyes burn easily in any water ive been in, chlorinated or not, so i cant see anything anyway
Avatar's creators would have their minds blown by these lightbending topics.