Please note that the image from "how stuff works" explaining how the 3D glasses work is incorrect. A red tint only lets red light through and a blue tint only lets blue light through.

Thanks for your concern. The arrows in the image represent the image that each eye views.

Blue lens filters the blue and only allows that eye to see red image and the red filters the red and only allows that eye to see the blue image.

That's not right. Blue filters let blue light through, and will block red images. Red filters only let red light through. That's why the light appears blue or red through them - they block all frequencies other than their colour.

If you don't believe me - try it. We have a red laser here that is blocked by a blue filter, but passes through a red filter - as you would expect. The diagram is therefore incorrect.

So explain How the decoder (Red) lens works: With your idea when looking through red lens it would only see red image. Wrong! Red filter blocks everything that is red in the image and only allows the blue hidden message to be reveled. Or How the Wobble viewer works: Blue strip of film lets you see red image and red strip sees the blue image. Works the same for 3d Anaglyph.

Test it yourself: Type the word red in red and the word blue in blue on a white screen, look through the red lens, the only word you will see is the word blue.

By the way: You are the only one to complain in the 5 years it has been up. I did not create image, but copied it from another site.

OK, I did your experiment. Red written in red, blue written in blue. I look through a red filter and I see the word blue more clearly. This is because the blue text is now darker, the red text remains unaffected, and the white background has been filtered so that only the red frequency comes through. The red filter blocks the blue light, making the blue appear black. It lets the red light through unchanged.

So I repeat - a red filter only lets red light through, including the red of the text and the red in the white background. It does not let the blue light through, which is why it appears black. Same applies in reverse for the blue filter.

You are confusing light and dark here. As for why no-one else has complained... I couldn't say. But I am a scientist, based in University College London :)

Okay. I accept that. When ever I get a chance I will fix the image by changing the arrows (red to blue and the blue to red). I have not updated in 2 years and I am currently working on 80 2d to 3d images for one project due in 2 weeks time. Doesn't give me time to keep up with web page. (Just 1 artist for - Glasses design, 2d to 3d conversions, custom die -cut, lens effects, in house promotion, and web.)

Not your fault, William. I know the originator was howstuffworks.com. It's good of you to be thoughtful enough to care.

Good luck with the 3D work, and thanks for a nice discussion.

And this is the incorrect diagram that seems to be confusing so many people. As I hope you can work out, only blue arrows should emerge from the blue filter and red arrows from the red filter. Watch what you believe!

Unfortunately, my editor read my message in a quite different way. She thought I was saying, "even bird sh*t would be better than the current design" in quite an insulting manner. Oh no! It's true, maybe this is the first time an author has suggested bird poo to be on the cover of his book, but it was a real suggestion!

Luckily the confusion was smoothed out, and although I'm sure my editor still thinks I'm a minor nut, the cover was redesigned. Not with a big bird poop, but at least with a nice-looking bird and a decent bit of white poop splashing on the hat below. I guess that's what happens when you name a book Why Sh*t Happens. We're working on the Americanized text right now and the book will be available early next year.

http://www.newscientist.com/channel/opinion/mg19926692.300-review- ithe-undercover-scientisti-by-peter-j-bentley.html

Review: The Undercover Scientist, by Peter J. Bentley

PRAY you never have a day as hellish as this. Within 16 hours, the hero of this book gets a computer virus, squirts raw chilli juice in his eye and breaks his toe, little finger and front tooth, among other mishaps. The consolation for us is that every calamity illustrates more science, such as why milk goes putrid, or why diesel ruins petrol cars. None of the science is groundbreaking - everyday wonders get preference - but it makes for novel reading. It's stream-of- consciousness science, as if Leopold Bloom from James Joyce's Ulysses was a clumsy but observant engineer.

From issue 2669 of New Scientist magazine, 13 August 2008, page 45

...A quick look at a great fun paperback for anyone who has ever split a drink, burned the toast, had a computer crash, slept through the alarm, or made the bath overflow. In other words, all of us.

Peter J Bentley, writing as the undercover scientist, explains why these things happen, medically or technically for instance, in a way that a schoolboy could understand. I mean, there's a lot of talk about running cars or lorries on chipfat, but could you explain in one syllable words how, exactly? Well, he does. And did you know that lightning can and does strike the same place, twice?

I promise you, this is a fun one that is fascinating. Ever got the juice from chilli peppers in your eye? Not pleasant, because the chilli peppers contain a chemical which fools your nerve ends into believing they've been burned. Well he sets out his book in the form of a day when everything goes wrong for you, and he explains all of those everyday accidents and how they happen.

Science, he tells us, governs everything - or to be more specific, there's a set of scientific principles that rules everything around us. He makes it so understandable, and as I said, fun. He points out, as a kind of warning, that if we'd not invented superglue we'd never have been able to stick our fingers together. And if the mp3 playes hadn't come along, we wouldn't be able to drop the entire lifetime music collection down the toilet by accident.

The benefits and the perils of science by Peter Bentley, and his Undercover Scientist, from Random House.

The Undercover Scientist - Peter J Bentley
Random House Books, £12.99

Bentley is a man with a degree in artificial intelligence, so He Knows Science. And he's decided to share it with us. Taking the example of someone having a shocker of a day, he reveals the secret science behind everything we do.. Ever over-slept? Slipping on shower gel in the bathroom? Or dropped a wine glass and wondered why is smashed that way? Bentley has the answers. Now you'll know why you're eyes feel hot if you chop a chilli then rub them (even though they aren't hot!). It might be a bit much to read all in one go, as there's a lot of info in there, but this is a book that opens up the world to you. Factalicious.

Yet another review! On Friday 20 June, in the popular science section of publishing news, The Undercover Scientist was listed as one of "Sue's Picks" for the Top Titles of the month. In her review she correctly pinpoints exactly where the title is aimed, so again it's nice to have a reviewer understand and appreciate this book.

TOP TITLES

RANDOM HOUSE

The Undercover Scientist

Peter J Bentley/

Random House books

9781847945235/3 July/£12.99

Good popular science bridging that difficult gap between abstruse theory and the Q & A market, with an author able to explain and enthuse. Even my poor brain could grasp the concepts he discusses. organised around one mythical day he shows why and how things go wrong, the scientific reasons for the mishaps in your life from leaking pens to computer crashes.

 

The online publishers Blackwell books are featuring The Undercover Scientist as one of their books of the month. You can see their promotion on the front page of their website. It's nice news to have on the day of its launch!