The Magic (and Mystery) of Mirrors

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How many times do you look in a mirror every day? Have you ever stopped to wonder how they actually work? Mirrors do strange things to our world, seemingly flipping everything so that what was right is left and what was left is right. But what if I told you that mirrors don’t actually flip the world left to right? The real magic of mirrors is far stranger and more interesting, as you’re about to learn.

Inspired by:
Gardner, Martin - The New Ambidextrous Universe: Symmetry and Asymmetry from Mirror Reflections to Superstrings

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[besmart]

I hope this video give you something to reflect on 🤓

Thanks for watching, I'm on Instagram and Twitter! @DrJoeHanson @okaytbesmart

[FrankLeeMadeere]

I always found it easier to imagine that every point in the mirror is just reflecting back what that point "sees", like a whole bunch of little lasers. Start with one point and work your way up. It explains every "weird" phenomenon perfectly once you can imagine it. There is no "flipping" or "reversals", just a true reflection.

[dentoncrimescene]

I was quite comfortable how mirrors work before I started watching this video, was then super confused for a while, then I ended up okay with it again by the end. Quite an odd experience.

[Beryllahawk]

Spent half this video going "mirrors bend light" and you went a whole different way with the explanation. VERY interesting! I'll have to go and ah...reflect on what I've learned.

[Katiethewizard]

As a printmaker who always has to carve or engrave words/images backwards so they print correctly, I understand all too well

[Hobo_X]

I have always felt that the mirror test is being far overly-exclusive. Cats don't pass the mirror test for example. Now this obviously isn't a very scientific example, but something I've always done growing up was whenever we would get a new cat, I would put them on the bathroom counter and see their reaction in the mirror. The "reaction" was almost always a complete lack of reaction. But if they saw any other cat in the room, they'd freak out because they haven't been assimilated yet. To me that has to be displaying _something_ about their brains, because how do they know not to freak out over their reflection?

[katetoolate]

The back to front flipping is very apparent to me when I try to put a hair pin or something on my head using a mirror. When I try to move to the right spot along my head, I usually end up going the wrong way. 😄
I saw this concept explained in another video before but this one covered more. Well done!

[manuelapollo]

I am a physics teacher and I have taught this lesson a few weeks ago. The book mistakenly say that the mirror flips left to right. I had to explain the students that no, it's not true. But the main lesson was how even simple phenomena can be very much counterintuitive.

[conlon]

To show a mirror writing, you flip it - from facing you to facing the mirror. It reflects what you show it - it doesn't flip it back. Write on a piece of paper with a pen and hold it up to a window, facing the window as you would have it face a mirror. Read it through the paper, and it's mirror writing. It doesn't reverse what it sees, it reflects it back as is, without changing it. The writing you show it is as it would look from the back of the page - you might be able to see both simultaneously if you use a felt-tip - and it's the same thing the mirror reflects back to you. If you write on condensation on a car window, it's a mirror image on the other side of the glass. If you write in the air, what the person opposite you sees is the same as what a mirror opposite you would see and show back to you. The same as if the person opposite you read writing through the back of a page you were reading. If you had see-through paper, such that you can see the writing from both sides, one side would appear as mirror writing. If you showed this page to the mirror so that the paper was orientated that you could read it, the reflection you could also read. Mirrors don't have their own left and right - unlike a person opposite you, your right is its right and your left is its left, it's not flipped, you're just so used to flipping it for another person's perspective, but a mirror's not a person. That's our problem. You show a mirror writing on one side of a page, and it doesn't read it, it shows you the writing as it would be if you could see it yourself through the page. Nothing is flipped, you just expect it to be, but a mirror doesn't have it's own perspective like a person or camera does, it uses your perspective. In a way, it enables you to see things, from your perspective, that you never normally could, like the other side of things from a side you never normally see them - as if you were looking at the other side of the object - say the sheet of paper - through it, rather than by turning it around to see that side, which reverses it when a mirror doesn't. I hope all this made sense.

[etownshawn]

Always fascinated me as a kid at the barbershop, seeing 2 mirrors facing eachother & infinite reflections inside them. Also, I want to buy that over-sized alarm clock haha

[Ghost-Raccoon]

We think that a mirror flips left and right, because if the see a person in the mirror, we expect that person to have walked behint the mirror and rotated 180° around the vertical axis. Because this is how we expect humans to rotate. Based on this assumption, that there is a normal person "in" the mirror that just rotated, we think that the mirror person has left and right reversed. We cannot imagine flipping front and back of a person.

[idraote]

This was far more complex than expected.
Also, I tend to notice asymmetries in the human body. I zoom on them automatically. My OCD is not happy about asymmetry.

[corviraptor]

5:55 mad props for using a blackwing pencil for style points

[IntenseVisuals]

This was way more interesting than I thought it was going to be.

[salsal]

This video almost broke my brain ☹️
Thank you for your amazing content!!

[zestyorangez]

It's no longer merely okay to be smart. It's now a command.

[fireriffs]

Another way to demonstrate this is to write on a transparent page, like the old overhead projectors used to use, and face front away from you. You can see through the back that it looks like it does in a mirror.

[aisekaisebc]

Flatland, A term coined by Edwin Abbot.
But something about Joe’e delivery and flat pun reminded me of Carl Sagan.
Keep up the good work, it’s always fun to watch you deconstruct a concept and explain it so everybody can enjoy learning it.

[bytekast]

I gotta buy one of these double-reflection mirrors (the one that doesn't "reverse" the image). I want to know how other people see me. Also it looks pretty cool to have one around.

[TMtheScratcher]

Actually I was more interested in the question from the beginning. Our body is symmetrical and this is astonishing if you try to imagine yourself from the perspective of a cell. The machinary behind cell differentiation which determines what a cell has to be is incredibly accurate to create symmetrical animals at this and even larger scales