Concave Mirror Demo: Pendulum

This video uses a foam ball to demonstrate the image formed by a concave mirror.

[DavidLS]

There was a mall near where I lived that had a giant concave mirror. You could walk into it and actually pass through your own reflection. They also had a life-sized concrete hippopotamus, but that's a story for another time.

[Klodshans]

I discovered this phenomena as a little kid at the dining table, viewing myself in a spoon

[NerdomancerKirou]

I was having a mental breakdown earlier from trying to imagine a concave mirror using only some text, and now i understand it all perfectly. Thank you for this demonstration.

[PriNcEoFSpAcE]

what I find more fascinating(sort of...it's really kinda of the same thing...but try and follow lol) than the ball switching, is the fact that the mirror can have both types of reflections simultaneously e.g. when the ball is close to the mirror it is "correctly" reflected, but the chairs and cameras further off are upside down.

[arrnr]

These Pepsi ads are getting smart day by day

[dimmap]

I can't stop watching this video, the more I watch, the more I get to understand the sketches in my textbook. Sir, I thank God I found a teacher like you!

[Ranstone]

I love the fact that when the ball is close to the mirror, it's not inverted, but the everything else in the mirror is.

[alhypo]

The ball should have four colors so you could see it reversing the image left to right.

[joeteejoetee]

They should use simple "real-time" optical demos like this to prime students to learn Geometry basics.

[syoudipta]

When the ball is further away from the mirror than the focal point, the concave mirror should form a real image as the same side of the ball. How are we able to see that image in this video? Or what exactly are we seeing when we see the ball is on this side of the focal point?

[bobbucks]

I was amazed by optical physics in school. Amazed someone a long time ago would sit down and figure out the math.

[trefod]

Demonstrations are sometimes all that is needed to get something. Brilliant!!!!

[Throbtometrist]

Optics is the best! This is a concise explanation with no math. Hopefully it gets people interested :)

[GonzoDonzo]

Good way to figure out whos stoned in class

[physicsdemos]

Nitin K raised another question: Can we see the real image at different angles, or we can see it only straight in front of the mirror? Answer: When forming a real image on a screen, the image will be in a certain location on the screen. If the object is centered in front of the mirror, the real image will be centered on the screen. If the object is not centered, the image will not be centered either.

[sccm]

This gives me such an intuitive understanding after reading my textbook and dozens of YouTube videos

[himanshujha]

When the image is inverted, it is a Real image. so how can we see it on the mirror?, pls don't say that my eyes are not right... I have searched this on many platforms and asked 1-2 teachers about this and my doubt has not been cleared until now. Thanks

[YTjndallas]

This confused me bc the mirror is 360’ What about the effect on the left and right? This must also switch, but the ball is only divided 180’. I would like to se this demo with four color patterns divided in fourths. My imagination tells me that the ball’ reflection will appear to spin?

[urAnusFighter]

What i find interesting about this demonstration is that this is a great example of what a 4th or 5th dimensional object would look like passing through our 3rd dimension

[dale]

The concave mirror with a pendulum. Otherwise known as instant migraine mirror.