yego.me
💡 Stop wasting time. Read Youtube instead of watch. Download Chrome Extension

Can You Solve This Shadow Illusion?


3m read
·Nov 10, 2024

We have that card with a little round hole in it, and what I want you to do is hold it up, um, and try to cast a shadow on that wall there. I want you, before you do it, to predict what we're going to see. Shadow of the card? Shadow of the card with a little hole in it? We will see that figure enlarged on the wall. It's not very pronounced, but you can actually do see the little hole in it—and of course me!

So, Cole, woohoo! My next question for you is: we have this card. What's that like? It's big, a hole! Can you tell me what size circle we're going to see, like, compared to the other one? Bigger—like twice the size maybe, but still the card with a larger round hole. What do you see? Bigger hole: the card and the hole slightly bigger than the previous one—the same thing, just larger.

Okay, what I want you to do is the same size though; it's approximately the same size as the last one. Why don't we compare it? Here you go. You're right, it is—the one's just fainter than the other. Oh goodness, it actually looks about the same—same size hole! I can't believe that—it's must be the sun playing tricks with my mind.

What about here is really going to test you, right? Okay, uh, tell me about what's on that card. It's a—before you put it up—a triangle? Yeah, okay, so what do you expect we will see on the wall? A triangle, but I wouldn't be surprised if it was a circle. What are we going to see? A triangle, I'm certain.

Okay, let's have a look. Oh wow, that's awkward for me! It's a circle! It'll be a triangle. Well, we're not going to see a triangle. Why not? 'Cause everything else has been a circle, so it'll be a circle. I'm sticking to a triangle! Okay, it's a circle. Look, I'm interested. Well, there you go, it's a circle. Do you want to compare it to the one of the others? I'll give you the bigger one.

Oh my goodness, I really like this project! I'm learning something. The sun is definitely playing tricks on my mind. The sun is deceptive. That's weird. Why are we seeing circles with all these cards, regardless of the shape of the hole? I really don't know; I'd like to know. When you take away the definition from any kind of shape, it ends up being just round to our eyes.

There, for example, you get a perfect triangle, but it was a pretty decent circle from back. So, it must—you must get to a certain size. Here, it doesn't matter what shape it is, it's just turned back probably. Why is it going into a circle, though? Look at the sun; it looks around, doesn't it? So, I'm not sure if that's got anything to do with it.

Well, the light is going through these little holes, and it is the sun. The sun rays just sort of, um, going through the little holes making a circle of the sun. I don't know; you told me exactly. You nailed it! What we're looking at there is actually an image of the sun.

Really? Yeah, oh wow! The Earth's round and the sun's round, and yeah, the sun—the sun's round, I guess. The building's round? The building's round. Is it? No, the building's not round! So, what we're seeing is a projection of the sun. I've never thought about it before.

I think that you actually know, and I think you have actually thought about it before, but I think you're not queuing that right part of your brain that knows the answer. Yeah, probably! There's a part of your brain that knows the answer.

Well, I did photography at school, um, and we did pinhole cameras. The hole actually reflects what it's showing on the wall. So what's that? So it's the sun! Well, there you go, I learned something today, Derek.

More Articles

View All
My Advice for Each Stage of Life
There’s a life cycle: right, your teens, your 20s, your 30s, and so on. Every phase is a little bit different, or quite a bit different. People have asked me, in their 20s, what is good advice for their 20s? You are about to go independent. You were depe…
Example dividing a whole by a unit fraction
Let’s think about what 3 divided by 1⁄4 is equal to. Pause this video and see if you can figure it out on your own. And I’ll give you a hint: take three holes and divide it into pieces, or sections, that are each one-fourth of a hole. Then think about how…
10 Stoic Keys That Make You Outsmart Everybody Else (Stoicism)
In the heart of a bustling city, there was a young man who seemed to have it all: a great job, a loving family, and a vibrant social life. Yet every night, he found himself staring at the ceiling, gripped by an unsettling feeling that something was missin…
How to find a mentor - the RIGHT way
What’s up you guys, it’s Graham here. So this is probably one of the most important topics that I’m going to be discussing so far, and it’s about mentoring. I feel like so many people are so caught up right now in trying to find a mentor. They think that …
The Truth About Toilet Swirl - Northern Hemisphere
Hey it’s me Destin. Welcome back to Smarter Every Day. Here’s the deal. I’ve created a video in the northern hemisphere and Derek from Veritasium has created one in the south. You have to synchronize these two videos in order for this to make any sense, b…
Khan Academy "Hamilton" song
How does a website platform educational and non-profit shot in a cramped damp shoebox of a closet as an office built by a Bengali trooper? This product turned out to be the schoolhouse of the future. The not recruit hedge fund suitor without a suit got a …