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Invisible Man

Science brain teasers require understanding of the physical or biological world and the laws that govern it.


Puzzle ID:#8489
Fun:*** (3)
Difficulty:*** (2.85)
Submitted By:electronjohn*us****
Corrected By:boodler




Cindy, a High School cheerleader, told her fellow cheerleaders that she was worried about changing for practice in their locker room. Seems that she over heard the science teacher, Dr. Smith, telling the Principal that he had just invented an invisibility potion which turns whoever drinks a sip of the potion completely invisible for 24 hours. The bad news was that someone had stolen a bottle of it from Dr. Smith's lab. Cindy was worried that the thief was a guy and that he might already be invisible, hiding in their locker room and waiting to watch them undress. Jane, the Head Cheerleader and President of the Science Club, believed Cindy since she knew Dr. Smith was working on the potion, but told her they had nothing to worry about. Since Jane did not steal the potion or know who had stolen the potion, how could she be so sure their privacy would not be compromised?

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Nov 17, 2002

never heard of such a smart cheerleaders b4!... lol just joking..don't take it personally all you aspiring cheerleaders out there

Nov 17, 2002

That really is amazing. I had not known that before. I have a question, though. Just because he's invisible, that doesn't mean he isn't there. Wouldn't he still be able to absorb light and cast a shadow and all that?
Nov 18, 2002

Good question Piffle. If he were really invisible then all light in the visual spectrum (380 - 700 nanometers wave lengths) would pass right through him as if he were not there. If he absorbed any of the light in the visual spectrum then he would appear as a dark silhouette, which would make him visible. How dark would depend on how much light he was absorbing. Of course this is all just theory on my part since no one has been able to become invisible as far as I know. The reason why I made it a potion is because potions imply some kind of physical/chemical reaction to the user. If you are talking about some kind of magic spell or magic ring (i.e. Bilbo Baggins) that would turn someone invisible then you could image that the spell or ring could also give the recipient some kind of magic sight. This is something I did not want to get into since “magic” is impossible, by its very definition, to discuss scientifically.
Dec 26, 2002

There's one correction that I would like to make to electronjohn's statement. The" visual spectrum" is not 380 to 700 nanometers, it's 400 to 700 nanometers.
Dec 30, 2002

400-700 nm is sometimes used as the range of visual light for humans. These valves are easy to remember since they are nice round numbers but as you may have guessed it is very unlikely that we would just happen to have a range of visible wavelengths that starts and stops on such nice round numbers. Other sources list 380-700 nm as the visible wavelengths such as ( which states: “Humans can see light with wavelengths ranging from 380 to 700 nanometers (a nanometer is one billionth of a meter), with red being 700 nanometer and violet being 380 nanometer."
My guess is that even these numbers are rounded averages and depending on the individual you get a few nanometers more or less on either end of the spectrum.

Avitar does bring up a good point, always question the validity of the information we are spoon feed. Many “fact” that we are given by teachers, text books, etc. turn out to be incorrect or incomplete. Check other sources, run your own test if possible and above all THINK about what makes sense.

And Cutebluetiger, I know enough to release that I know almost nothing when compared to the total sum of human knowledge. About living, I went skiing in Colorado last week. Does that count?
Jan 08, 2003

Hmm, Didn't care for this brainteaser when reading answer. I reckognize that this riddle puposely did not use the words "magic" to attempt to keep reader to follow true laws of phisics (and hence the solution makes sense). I guess what troubles me is that I dont know of any nonmagical form at this time to make some one invisible. Meaning, what IS invivsible. Glass is invisible under the right conditions but you can still see it under other conditions. Maybe some day we will have technology to make someone transparent like glass but still visible like a glass vase. If we could actually make someone completly invisible under all conditions, I think this would be new technology and that maybe they could actually see. LOL, sorry for ranting and raving. In puzzles, I think their are clear puzzles where the wrong assumption is genuinly the key to the puzzle but I have seen many puzzles where the assumption that is the "key" makes people say "Oh, no way!!, That's silly. I guess I am anal, factual, and mathematical by nature in puzzles. Final comments, you fooled me! (This is a neat website, I have many to possibly add but will check archives first.) Chili-N1
Jan 16, 2003

also, if the person was spying on the girl in the shower, she would be able to tell due to the deflection of water droplets.
Jan 16, 2003

what is the potion has the same affect as the chameleon's ability -- then they would still be able to see but remain camoflauged (invisible to others).
(user deleted)
Jan 22, 2003

i thought it was ok i didn;t like the part wher she was afraid i think cheerlearders should like to be seen
Feb 25, 2003

A Japanese scientist has developed a coat which appears to make the wearer invisible.The illusion was part of a demonstration of optical camouflage technology at Tokyo University.It is the brainchild of Professor Susumu Tachi who is in the early stage of research he hopes will eventually make camouflaged objects virtually transparent.The photograph was taken through a viewfinder that uses a combination of moving images taken behind the wearer to give a transparent effect.
Feb 25, 2003
Feb 26, 2003

Very interesting. Although it is far from making the wearer invisible the picture does show the head of the person in the coat sticking out. I suppect that is because they would not be able to see through the material of the coat.
May 06, 2003

Wow. Cool. Perverts out there better invent something better if tey want to take a peek =P
Nov 15, 2003

A little TOO scientifical for me...Thanx for the information though....
Jan 15, 2005

pretty well thought out
Mar 02, 2005

I was just reading about a proposed "stealth" device. Invisible simply means "not visible" it doesn't mean light passes straight through you. Suppose light is absorbed in the retina (so the peeper can see) -equal light emissions could be generated making the visible black spots - Invisible. It's the camoflauge principle found in nature to the extreme. I do not accept this teaser!
Mar 02, 2005

Smek, if you do not accept this teaser then I suggest you reread it and the answer again. In the teaser I clearly state that Dr. Smith "had just invented an invisibility potion which turns whoever drinks a sip of the potion completely invisible for 24 hours." Note that it says completely invisible and not camouflaged or hard to see. Also the answer makes many strong points as to why someone that is completely invisible could not see. Please reread the following: "In order to see light needs to be absorbed by our retinas. If a person were completely invisible all light would pass right though them and they would see nothing. If the retinas were somehow able to absorb light then there would be two black spots in the air where they were and they would not be completely invisible. In this case light would then hit the retinas from all angles, since the head would no longer be opaque, and blind the invisible thief. Plus the lenses in the thief's eyes would not work so no image could be focused onto his retinas."

Note also that this is a potion which means that it affects the body, presumably at a cellular level. Nothing in that suggests the presence of any electronics that would be needed to create "stealth technology". No radar, no light sources, no computer chips. But thanks for reading it and thinking about it even if your conclusion does not agree with mine.
Mar 02, 2005

Also, and maybe more to the point, how could the thief see if some device was right in front of his eyes emitting light to camouflage the black retina spots? I mean how could he eye anything other than the devices emitting the light right in front of his eyes?
Jun 10, 2005

Reading deeper into your 'question'. If your body was indeed invisible, that would still make your clothes visible, thus you would have to be naked to be able to be really not seen. One thought though, would the food you eat, the contents in your stomach, etc, be visible???
Jun 16, 2005

extremely easy. i knew about that a couple of years ago.
Jul 09, 2005

that was really good and interesting
Jan 08, 2006

Well I knew that I wouldn't know this one, but found it really interesting, thank you.
Feb 01, 2006

I really don't think that a technical rationale (i.e. invisible eye would not be able to see) is really 'fair' as an answer. If we are going to suspend disbelief enough to accept the notion of a working invisibility potion, we should be entitled to go whole hog and accept the standard Hollywood depiction of invisibility--that is, that an invisible person would be able to function normally in every way, other than being seen. Going by your logic, invisibility would be almost instantly lethal anyway; stripping hemoglobin of its pigmented character would certainly rob it of its oxygen-carrying capability.

(Well, time to go play robozapper.)
Mar 26, 2006

the whole idea is just a little frightening to me ! not about the invisible man in the locker room , but the answer i don't know why , just sent chills through my body!!!!
Jun 08, 2006

Props to you, ElectronJohn. I like this teaser a lot. It was well worded, both in story form and in detail. Everything was clear and nothing misled from the premise.

Very satisfying to solve, and I felt confident of my answer before clicking "Show Answer" (which isn't always possible in some teasers.)

Good job!
Feb 19, 2007

I technically correct answer for a technically impossible feat. What's the point? Its not science. This should be under trick or riddle.
Apr 22, 2008

Dang, this is so cool...
Jan 15, 2010

good one. I have no idea what everyone else is talking about. I just laughed and moved on. WHO REALLY CARES WHAT CATEGORY IT IS???!!!

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