WorldOfEngineering
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The Jastrow Illusion
The Jastrow illusion is an optical illusion attributed to the Polish-American psychologist Joseph Jastrow. In the video, the two toy railway tracks are identical, although the lower one appears to be larger.
The oldest reference to this illusion can be found in The World of Wonders, an 1873 book about curiosities of nature, science and art.
There are several competing explanations of why the brain perceives the difference in size between the ring segments. The most commonly used explanation is that the brain is confused by the difference in size between the large and the small radius. The short side makes the long side appear longer, and the long side makes the short side appear even shorter.
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Reekou
This used to make me furious as a kid
oldskoofoo
Duh, it’s magic wood
Turbolibros
richiWebKing
3Davideo
The problem with spooning: an illustration
iquestioneverything
Yeah it's cause you're not lining them up to be even. You're matching the long side of one with the short side of the other.
cthedon
Gosh thank you... Was looking for this comment
OaksParcel
It's hard to be the big spoon with a girl that's around the same height as you.
OhB1KinOB
He is TRAINING to be a witch!
nommon
It doesn’t really count with the camera angled like that. You’re adding foreshortening.
JackoComputerJumper
It's a conspiracy
GuyFromDeathValley
it's.... fake news?
JackoComputerJumper
Fake.... News?
ToasterDent
I didn't believe it, so I made a video of a copy & paste and damn if they aren't the same size!
spaolo3140
i don't think it's the right way of checking
sydneyAVDE
He should have switched the tracks!
Antionio
This illusion has a good track record
UnluckyScarecrow
The fact it's a video also. One closer to the camera appears larger, but because it's a video we don't have depth perception to catch it.
StewedTomaters
That's exactly what I was thinking. In 3D it wouldn't fool the eyes.
Muunk
This totally derailed my thinking.
ttweld
The outside arch is longer the the inside....
Gunslinger2071
And?
footInMouthAndHeadUpAssSoWhatYouTalkinBout
No, it's because the world is flat
FunctioningWorkaholic
And because magnets!
PTNLemay
Yeah but still... Pretty counterintuitive
Ocek
Right, but draw an imaginary line along the outermost point of the outside arches. You'll see the illusion even more strongly then.
Thelrishlnquistion
MeatSparkles
Literally me watching this magic.
Stinkybuttpants
I'm thinking about How I can use this to make my junk look bigger?
MrHainey
athletes need to see this NOW before the 2020 Olympi..before the 2021 Olympics... oh fuck it.... before the (whenever) Olympics.
TheGreatAndPowerfulSage
What is this called in the World of Wonders book? I don't see Jastrow Illusion in the Index... Lots of other neat stuff, though.
Sphinxycat
And now I’ve got to walk back down stairs to kids playroom. Thanks
LongtimeLurkerFirsTimePoster
Fake Views.
buzzbladz
.
yokohamadreamer
erock1918
Look at where the edges start. Both arcs of the top track start to the left of where the lower track's arcs begin. (1)
erock1918
As a result since the top track edges start more to the left it's easier to understand why they end further left (2)
mudstew
Thank you! Your explanation made it make sense.
punchin83
If I imagine 3 parallel lines on top of it, 1 on the left side and 2 on the right connecting respective corners, they look the same.
cathou708888
I buy a railroad to me nephhew and now i just want to open his gift !
returningtothetangentathand
Does the lower camera angle contribute to this?
Lifk
Yes to accentuate it and make it easily observable in a gif i guess
Cinemagik
It's the angle of the track end. Line up outermost point instead.
tyrfin
People roll their eyes at you a lot, huh?
dasclown
I wondered that too. I wasn't to see him use his hands and touch both sides of the tracks to see if that "fixes"the illusion.
thoushaltnotpass
The wide angle lens definitively exaggerates it
FINNSTAR7
Barely. The illusion still holds from a top view as well and is just as impressive
RedKale
I put the lower part of this image over the upper part. Can’t believe it worked.
ToasterDent
FINNSTAR7
Make sure to rotate so the backsides are flush
Beezlebubble
This helps and helps me understand it now, thank you
LeMegachonk
It's actually more obvious how the illusion works when seen from directly above.
Smacketywack
It’s a track!
FuturamaSleeper
LegendaryGarf
Brio-liant
Kaysmira
Thank you for making the internet great for me today.
Putitinyomama
DumbandConfused
Needs moar conductor hat
FunctioningWorkaholic
Easy to see for the train'd eye.
CgnCalling
The fat conductor will be cross!
Nanuek
He's not actually fat, just being spooned by another conductor. It's an optical illusion
heyletsbefriends
darthbuttersticks
Buchp
What a lovely knitted sweater
iConfirmAnythingAndEverything
Your grandmother made me one.
EntropyReign
@iConfirmAnythingAndEverything probably:
noyoutellmeYOURpasword
You can do this with M4/M16 mags.
kerlkerber
Especially AK mags.
Frostbreaker1
Found the American
Patient00
Only they still use fucking m16
Frostbreaker1
Canada uses a Canadian made version of the M16
Patient00
I choose to believe the canadian version is better than the american for the sake of americans sucking at making guns
Frostbreaker1
I have no idea. I don't know why Canada would be good at making guns lol. Its made by Colt Canada, thats all I know
noyoutellmeYOURpasword
Diemaco is now Colt Canada. Diemaco was superior in every aspect, until Colt got their dirty hands on it. Cutting corners to maximize profit