🦛

Did it spray concrete shit everywhere?

Ohhh! I want that story now!

@@emceeboogieboots1608 If you insist. It was a life-sized concrete hippopotamus. Little kids liked to sit on it. (I never said it was a good story.)

@@DavidLS1 in the future, if I ever feel I’ve disappointed someone, I can always say: At least I didn’t use that hippopotamus story 😀

You swing your balls in front of a spoon at the dining table??

There is no spoon.

Yup, all these guys get PhDs for doing stuff we figured out as kids

@@seanfaherty , and getting paid to do it!

*phenomenon

Me too lol I couldn't even think how it is possible that there is no image when the object is on the focus point, until now.

you can try this at home by looking at spoon

Hi, If anyone is interested, I published a book called "Making Technique for Large Diameter Concave Mirror, Convex Mirror, and Thin-Sided Lens" on Rakuten Kobo E-Book platform. In the book, molding silicone, clear epoxy (or clear plastic resin), polyurethane, air pumping tool, air vacuum tool, wood chips, acetate paper, etc. I mentioned the methods that will allow you to produce meters of diameter using. In this way, you will have the knowledge and experience that you can carry out your projects for astronomy and solar energy in a practical way. Have a nice day.

Hope that by now you realized you can google up stuff BEFORE you have a mental breakdown trying to imagine it...

Text?

actually u can notice it e.g. @2:22. Also, it only happens when the object distance is larger than the focal length.

I think you're correct with the effect you suggest for this situation . However for a flat mirror there is a head scratch conundrum to pose :-" if a mirror reverses left and right then why not also top and bottom ".

@@charlesdickens6706 Well that's just semantics depending on how you define "reversing". But saying a flat mirror reverses an image left to right but not top to bottom doesn't make sense. Imagine if you lie down on you right side facing into a flat mirror. Now will think the mirror is reversing the image top to bottom (because your left side is now the top)? I'd say a flat mirror is not reversing it left to right nor top to bottom. If you could grab your reflection from the mirror's perceived 3D space and superimpose it over your physical self in actual 3D space, the face of the mirror you would be poking out the back of your head but your left arm would still be intersecting with its reflected self. So the image is being reversed front to back.

@@charlesdickens6706 A flat mirror doesn't reflect left and right. It's our brain that expects that it should.

@@charlesdickens6706 You're the one reflecting it that way, not the mirror.

thought the same. lol

Boy, that was clever.

Generation next?

are getting smart-er? Yeah!

No, your the Pepsi Rep.

Exactly

3blue1brown

Hi, If anyone is interested, I published a book called "Making Technique for Large Diameter Concave Mirror, Convex Mirror, and Thin-Sided Lens" on Rakuten Kobo E-Book platform. In the book, molding silicone, clear epoxy (or clear plastic resin), polyurethane, air pumping tool, air vacuum tool, wood chips, acetate paper, etc. I mentioned the methods that will allow you to produce meters of diameter using. In this way, you will have the knowledge and experience that you can carry out your projects for astronomy and solar energy in a practical way. Have a nice day.

Hi, If anyone is interested, I published a book called "Making Technique for Large Diameter Concave Mirror, Convex Mirror, and Thin-Sided Lens" on Rakuten Kobo E-Book platform. In the book, molding silicone, clear epoxy (or clear plastic resin), polyurethane, air pumping tool, air vacuum tool, wood chips, acetate paper, etc. I mentioned the methods that will allow you to produce meters of diameter using. In this way, you will have the knowledge and experience that you can carry out your projects for astronomy and solar energy in a practical way. Have a nice day.

Hi, If anyone is interested, I published a book called "Making Technique for Large Diameter Concave Mirror, Convex Mirror, and Thin-Sided Lens" on Rakuten Kobo E-Book platform. In the book, molding silicone, clear epoxy (or clear plastic resin), polyurethane, air pumping tool, air vacuum tool, wood chips, acetate paper, etc. I mentioned the methods that will allow you to produce meters of diameter using. In this way, you will have the knowledge and experience that you can carry out your projects for astronomy and solar energy in a practical way. Have a nice day.

My hs history teacher looked and sounded like this guy, I don't think I was awake for 1 class 😅

Very good point,i imagine so too.

Would be interesting to see, don't think you'd get a spinning effect though, might even be if you imagine every line you could draw from the centre of a circle to the edge (cross section of the ball), every line might actually be effectively mirrored in a perpendicular plane that passes through the centre of the circle, so on a clock face the 1 and 7 would switch places, and 10 would swap with 4 etc, due to all the spherical curvature going on with the mirror and ball, in this case all the imaginary lines in the top half of the circle get mirrored across the centre into the bottom and vice versa causing an apparent vertical mirroring effect, when it's actually a circular mirroring across all angles which as I write this I realise would give the same end result of a simple horizontal+vertical mirroring. But what ever would happen I think it would still happen suddenly as it passed back and forth through that middle point rather than looking like it is spinning. After thinking about it that much I definitely want to see it also

He demoed this with his hand at 0:29 and 1:07 :-)

@@biancabonet Maybe if I could find a little LSD after 35 years? Lol.

You get reflection symmetry through a _point._ Looking head-on, each point on the edge of the ball gets reflected to a point on the opposite side of the ball. (Technically, you get reflection symmetry through the point at the center of the disk defined by looking at the ball head-on, which is the same as saying "the image of the ball _projected_ onto a 2D plane normal to our line of sight.) So to answer your question: No, you wouldn't see spinning. Imagine a ball with 4 colors: red, yellow, green, blue, say, going clockwise, starting with red on the top right of the ball. In the reflection when the ball is far from the concave mirror, you'd see green, blue, red, yellow. Fun fact: it turns out reflection through a point in a 2D plane is equivalent to two reflections across orthogonal lines (e.g., reflecting across the x-axis and then y-axis, in either order). Fun fact 2: reflection through a point in a 2D plane is equivalent to a 180° rotation. *Note*, however, that you wouldn't see _any spinning,_ as this "rotation" is just the operation that you imagine to map the colors on the ball to the location of the colors in the reflection. In some sense, the "rotation" happens the instant the ball crosses the focal point and the image switches instantly to its "rotated" version. Hope this helps. Sorry if the words are confusing-I tried to keep everything clear.

Yeah, it's weird. We used to live in a world where we'd comment that the CGI was "looking almost real". Now we comment that our reality "looks almost CGI". We're losin' it, a little more every day. 😬☹️

@DogMan Haha.. I was going to throw a flat earth comment in as well.. But... I saw this and thought I'd just laugh instead (and write a short comment that actually got progressively longer as I decided to explain myself)

That is kind of redundant saying. They don't need to be from infinity. You can get parallel rays by having, let's say, an array of laser pointers. The point is, when you have a normal source of light (bulb, candle,...) at non-infinity, the rays go from its center in all directions. If you have a distant source (like the Sun), it still goes in all directions from the Sun, but the rays hitting your location are almost parallel. If the source is in infinity, it would be truly parallel...

The thing is, it works also in the opposite way - parallel rays converge to the focal point (that is how the parabolic antenna works, the dish focuses the signal to the small receiver), but if the light source IS in the focal point, the reflected rays will be parallel (that is how some car lights work)

Sometimes newcomers in KZfaq update algorithm slightly, then KZfaq end up showing old videos ;)

So why isn't this yourself?

Woah, dude!

By the looks of it, no one is in class, probably because all the seats are upside down. They must all be in a heap of the ceiling.

😂😂😂 Not saying I'm stoned, but I would've loveddd to see like 185 more seconds of that ball going back and forth and back and forth at the end....

@@kaylor87 i am stoned and i approve

@@maximeduchalet4662 😂😂

Woah! Do you know where I can view this? Is there footage online? That seems like something I'd pay to see in person. MOSI the Museum Of Science and Industry has some really cool demos like that, such as a huge indoor tornado simulator and a massive fire vortex, but nothing like what you described.

@@DanteYewToob I have looked for it without success. I think it was an exhibit in a Hultons Boys & Girls Exhibition in Olympia London in the 50s or 60s (I am in my 70s) These were created to encourage interest in Science & Technology (worked for me!)

Another physics demo is conservation of energy where you hold the ball right next to the mirror and release it and it swings back and will never hit it.

If u mess this one up, u could just use that as your inelastic collision demo, as the mirror steals all the ball's energy when it shatters. Then just rewrite your lectures a bit to work some Newtonian physics into your optics class and ur set.

This demo has all to do with the tangent function. It's part of how the thin lens equation is derived. Similar triangles and all that. The image goes to and fro infinity. Negative infinity too. It's amazing.

*If the object is on focal point in concavity mirror that mean* *Position of the object at focal Position of the image at the infinity* ♾️ *Size of the image -highly inlarge* *Nature of the image -real and inverted* *Answer by indian 🇮🇳 student*

the retina of the eyes of we the observers, are the screens. The light rays from the real image arrive on the retina (screen) of our eyes.

Hi, If anyone is interested, I published a book called "Making Technique for Large Diameter Concave Mirror, Convex Mirror, and Thin-Sided Lens" on Rakuten Kobo E-Book platform. In the book, molding silicone, clear epoxy (or clear plastic resin), polyurethane, air pumping tool, air vacuum tool, wood chips, acetate paper, etc. I mentioned the methods that will allow you to produce meters of diameter using. In this way, you will have the knowledge and experience that you can carry out your projects for astronomy and solar energy in a practical way. Have a nice day.

Sir I asked," A real image WITHOUT A SCREEN can be seen from other angles or can be only seen from straight in front of the mirror ? "

Anyway my doubt has been cleared sir.Thank you very much sir for clearing my doubts.You are a wonderful teacher.

Without a screen, you can see the image from a variety of locations, not just on the axis.

Yes sir.

I really want to know how the moon reflects himself equal from all sides of the plane

Google "Walkie Talkie building London" which was known to MELT cars

Thanks!

@@physicsdemos Hello sir, I have a question. I don't have a double sided mirror at home. But is the front side of the mirror concave and its opposite a convex? Or its front a plane mirror while its opposite side a concave?

@@xyz-vl8ri Hi, If anyone is interested, I published a book called "Making Technique for Large Diameter Concave Mirror, Convex Mirror, and Thin-Sided Lens" on Rakuten Kobo E-Book platform. In the book, molding silicone, clear epoxy (or clear plastic resin), polyurethane, air pumping tool, air vacuum tool, wood chips, acetate paper, etc. I mentioned the methods that will allow you to produce meters of diameter using. In this way, you will have the knowledge and experience that you can carry out your projects for astronomy and solar energy in a practical way. Have a nice day.

Hi, If anyone is interested, I published a book called "Making Technique for Large Diameter Concave Mirror, Convex Mirror, and Thin-Sided Lens" on Rakuten Kobo E-Book platform. In the book, molding silicone, clear epoxy (or clear plastic resin), polyurethane, air pumping tool, air vacuum tool, wood chips, acetate paper, etc. I mentioned the methods that will allow you to produce meters of diameter using. In this way, you will have the knowledge and experience that you can carry out your projects for astronomy and solar energy in a practical way. Have a nice day.

No concave or convex mirror has a perfect arc or evenness, especially a cheap one like this!

yes the focal point, itd be like a microscope, every defect of the less-than-perfect mirror surface magnified.

If you make the mirror as near to perfect as you can then any remaining distortions are due to defects in the ball surface.

I wonder what would happen in a hypothetical perfect mirror. I imagine it would get bigger and bigger until it reaches a infinitely small point before switching ?

@@danilooliveira6580 The image is still a one to one representation. It appears bigger because the entire area of the mirror is reflecting a smaller section of the ball but is not enlarging any one section of the ball!

Same doubt

Pls help

Hi, If anyone is interested, I published a book called "Making Technique for Large Diameter Concave Mirror, Convex Mirror, and Thin-Sided Lens" on Rakuten Kobo E-Book platform. In the book, molding silicone, clear epoxy (or clear plastic resin), polyurethane, air pumping tool, air vacuum tool, wood chips, acetate paper, etc. I mentioned the methods that will allow you to produce meters of diameter using. In this way, you will have the knowledge and experience that you can carry out your projects for astronomy and solar energy in a practical way. Have a nice day.

@@alihaydartunc7249 is everything ok at home fr tho 🌚😅😂

Hi, If anyone is interested, I published a book called "Making Technique for Large Diameter Concave Mirror, Convex Mirror, and Thin-Sided Lens" on Rakuten Kobo E-Book platform. In the book, molding silicone, clear epoxy (or clear plastic resin), polyurethane, air pumping tool, air vacuum tool, wood chips, acetate paper, etc. I mentioned the methods that will allow you to produce meters of diameter using. In this way, you will have the knowledge and experience that you can carry out your projects for astronomy and solar energy in a practical way. Have a nice day.

Sorry, I mean virtual

Asmi, I'm glad the videos are useful to you. The image is virtual when the object is inside of the focal point, and real when the object is outside of the focal point. Through the mirror, you can see both real and virtual images, as shown in the video. The difference is that when the object is outside of the focal point, you could also see the image on a screen, that is, you could put a screen in the image plane and see the image, if the object is bright enough.

Hi, If anyone is interested, I published a book called "Making Technique for Large Diameter Concave Mirror, Convex Mirror, and Thin-Sided Lens" on Rakuten Kobo E-Book platform. In the book, molding silicone, clear epoxy (or clear plastic resin), polyurethane, air pumping tool, air vacuum tool, wood chips, acetate paper, etc. I mentioned the methods that will allow you to produce meters of diameter using. In this way, you will have the knowledge and experience that you can carry out your projects for astronomy and solar energy in a practical way. Have a nice day.

@@boydedwards5475 Hi, If anyone is interested, I published a book called "Making Technique for Large Diameter Concave Mirror, Convex Mirror, and Thin-Sided Lens" on Rakuten Kobo E-Book platform. In the book, molding silicone, clear epoxy (or clear plastic resin), polyurethane, air pumping tool, air vacuum tool, wood chips, acetate paper, etc. I mentioned the methods that will allow you to produce meters of diameter using. In this way, you will have the knowledge and experience that you can carry out your projects for astronomy and solar energy in a practical way. Have a nice day.

Same doubt

same Q, have you found the answer?

Hi, If anyone is interested, I published a book called "Making Technique for Large Diameter Concave Mirror, Convex Mirror, and Thin-Sided Lens" on Rakuten Kobo E-Book platform. In the book, molding silicone, clear epoxy (or clear plastic resin), polyurethane, air pumping tool, air vacuum tool, wood chips, acetate paper, etc. I mentioned the methods that will allow you to produce meters of diameter using. In this way, you will have the knowledge and experience that you can carry out your projects for astronomy and solar energy in a practical way. Have a nice day.

The inversion occurs in all axes. You can see at 1:08 that he moves his hand from right to left, but the mirror shows the hand moving from left to right.