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The Optical Illusions Thread

Excellent ste, Garrick, well worth a few minutes of anyone's time! :)
 
Oooh, my eyes have gone all funny now . . .:)

I'd seen one or two before, but there were some interesting ones that were new to me . . .

Well done, our kid!

Carole
 
Probably my favorite is that the full moon appears about ten times as big at the horizon than when it's overhead. Nope, exactly the same, but the illusion is truly compelling.
 
Blind Spot Experiment.
Never seen that one before, seeing is believing, or not.
 
Was impressed with the small squares where the white boxes in the corner that kept changing to black.
The wheel was also well excellent.
 
lopaka said:
Probably my favorite is that the full moon appears about ten times as big at the horizon than when it's overhead. Nope, exactly the same, but the illusion is truly compelling.

I've often seen these "big moons" on Tv. But i never get to see one in real life. Is it just a camera trick, or can the moon actually appear to be huge when on the horizon ?

Or is it that you have to be on a certain lattitude to see it and the uk is at the wrong place.

(ie too far north. I wish someone would drag us 1000 miles south so we could be next to Jersey and get some better waether:D )
 
I once woke up in the night and saw what seemed to be a HUGE moon through my curtains. Didn't dare get up and look at it (for marital reasons!) but have wondered ever since if it was really the moon. This was in June I think, in northern UK.
 
zardoz said:
I've often seen these "big moons" on Tv. But i never get to see one in real life. Is it just a camera trick, or can the moon actually appear to be huge when on the horizon ?

Or is it that you have to be on a certain lattitude to see it and the uk is at the wrong place.

(ie too far north. I wish someone would drag us 1000 miles south so we could be next to Jersey and get some better waether:D )

I remember a camping holiday in Fleet, near Weymouth - next to the coast, during the summer time, many years ago. The moon appeared to be so huge and red in the sky, it was like something out of an SF film.
Presumably, dust in the upper atmosphere distorted the moon as it was low in the sky.
 
the floating sausage illusion

Bear with me on this one its worth persevering with.

point the first finger of each hand towards each other and touch the two fingertips together about 3-4inches infront of your eyes.(fingernails away from the face)

Now focus on the point where the fingers meet (magic eye picture style) and hold the focus.

Slowly move the fingers straihgt out away from your face and a chipolata sausage will appear between your fingers.

Now to float the sausage in mid air slowly move the fingers appart.

Grand finally time. suddenly point both fingers to the ceiling and the sausage will disapear.

Beat that copperfield, blaine, etc,etc.

Have fun, Keep trying.....
 
p.younger said:
Jesus Christ......

That's what I thought; 'Jesus Christ! It's Bill Bailey!'


Mah: I remember the Floating Sausage from when I was little...you can have hours of fun with a sausage, can't you?
 
Bill Bailey

I also see our Lord and Saviour Bill Bailey.
 
Did the finger thingey. Cool!

Although it looked more like a mini Hetza hot dog!
 
How does Dyson make water go uphill?


What a shower
James Dyson's uphill water feature has been the striking image of this year's Chelsea Flower Show. But how did he do it?
It certainly beats your common or garden water feature.

Inventor James Dyson, he of the bagless vacuum cleaner, has stolen the headlines from the gardeners at this year's Chelsea Flower Show with his "Wrong Garden".

A set of four glass ramps positioned in a square clearly show water travelling up each of them before it pours off the top, only to start again at the bottom of the next ramp.

It is a sight which defies logic, and has become probably the most memorable image of this year's show.

Mr Dyson says his inspiration was a drawing by the Dutch artist MC Escher (he of Gothic palaces where soldiers are eternally walking upstairs, and of patterns where birds turn into fish).

"One of these is an optical illusion that shows water going uphill and round and round the four sides of a square perpetually," he says [see Internet Links]. "I wanted to create a series of cascades that are all on the same level - an everlasting waterfall."


BBC link

The link has a diagram and explanation.
 
Three cheers for Mr Dyson! Brit. ingenuity wins the day. Good on you,
Squire! You and your bagless vacuum have often warmed my cockles
on a cold Winter night. Often think of you on your rounds of your South
Korean (?) sweatshop as you contemplate your next publicity stunt.

Water uphill is it now? Keep rehearsing, Sir. Hope to see you walking
over it back to Blighty any day now! :cross eye
 
Well I saw it on the news and the water was blatantly going down the slope, not up it. The bubbles were going up. Maybe it's different if you're "actually there".

I don't like Dyson anyway, we have one of his hoovers and it's quite pathetic really. First the filter part broke on it, then the back wheel broke off. And it has always spat stuff out the back - like clumps of hair. Which is lovely.
 
I have, for some time, thought that seeing "auras" is the result of the slight movement of the eyes as one stares at an object or person.

(I was reminded of that when I read the following on the page that was the original link for this thread:
"Three Streams.
Apparent movement of the streams is created by afterimages as our eyes shift to examine the picture.")
 
Try this BBC test of your senses.

The first few questions are about vision, then it goes on to taste, smell, etc. The test is timed, and takes about 10 minutes.

I got a measly 12/20... :(
 
Yes, 12/20 here too;

As far as the moon is concerned,
The moon appeared to be so huge and red in the sky, it was like something out of an SF film.
Presumably, dust in the upper atmosphere distorted the moon as it was low in the sky.

apparently nothing to do with dust
see this
http://www.straightdope.com/classics/a2_110.html.
It really is an optical illusion; there is a refraction effect, but that makes the moon slightly squashed at the horizon and therefore smaller.
 
Optical Illusions and the Moon

The moon appeared to be so huge and red in the sky, it was like something out of an SF film.

The explanation I've heard--and the one that seems to make the most sense--is that when the moon is on the horizon, you are viewing it relative to familiar landmarks, like trees, mountains, or buildings, as opposed to seeing it hanging in the sky all by its lonesome, an effect similar to some of the optical illusions depicted in the first post's link. It's the same size but just looks a lot bigger positioned next to a tree.

The color, I'd guess, is the result of atmospheric conditions.
 
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