Challenge Questions Blog

Challenge Questions

Stop in and exercise your brain. Talk about this month's Challenge from Specs & Techs or similar puzzles.

So do you have a Challenge Question that could stump the community? Then submit the question with the "correct" answer and we'll post it. If it's really good, we may even roll it up to Specs & Techs. You'll be famous!

Answers to Challenge Questions appear by the last Tuesday of the month.

Previous in Blog: Wagon Wheels: Newsletter Challenge (03/22/05)   Next in Blog: Mirror Image: Newsletter Challenge (04/12/05)
Close
Close
Close
6 comments

Sunglasses: Newsletter Challenge (04/05/05)

Posted April 05, 2005 8:45 AM

The question as it appears in the 04/05 edition of Specs & Techs from GlobalSpec:

You come home early one afternoon to find your son and daughter bickering yet again... It's a sunny day and your son is holding his sunglasses up to the blue sky, twisting them, while your daughter is calling him a moron. ("Just put the sunglasses on, you moron!") You remind yourself that someday, when they're both off at college, you will miss these little exchanges and then say, "First of all, it's not nice to call your brother a moron. Secondly, he's not acting moronic and here's why." What's your explanation for his behavior?

Click here to view previous Challenge Questions.

Reply

Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.
The Engineer
Engineering Fields - Engineering Physics - Physics... United States - Member - NY Popular Science - Genetics - Organic Chemistry... Popular Science - Cosmology - New Member Ingeniería en Español - Nuevo Miembro - New Member

Join Date: Feb 2005
Location: Albany, New York
Posts: 5170
Good Answers: 129
#1

I know I'm missing the point here...

04/05/2005 11:28 AM

But I'd side with the daughter. I know sunglasses use polarizers to block the sunlight so I assume he's basically rotating a polarizer. However, the sun emits equal quantities of each kind of polarization, unless the atmosphere is polarizing the light in some way, I'm afraid his sister's right, he is a moron.

Reply
The Feature Creep

Join Date: Feb 2005
Location: Boston, MA
Posts: 1055
#2

there are a slew of reasons..

04/05/2005 11:43 AM

Here is a list of reasons:
1) If he is holding the glasses so that the sun shines through them onto a flat surface like a sidewalk; you can see an image of the sun more clearly and safely.
2) By holding the glasses an arms length away and looking at an object with horizontal and vertical lines you can see the amount of lens distortion in your sunglasses. (This distortion can lead to headaches and eye fatigue if you wear them too long.)
3) If the lenses are polarized he can be using them to find places the sky has partially polarized light. That is because the light coming from some parts of the sky is partially polarized.
Can anyone think of any other reasons?

__________________
"The future is here. It's just not widely distributed yet." -William Gibson
Reply
Power-User

Join Date: Feb 2005
Posts: 264
Good Answers: 2
#3

Sunglass Moron

04/05/2005 2:01 PM

Actually, he's looking for the ISS (International Space Station) and the orientation of the glasses do effect one's ability to detect such a large object orbiting the earth during daylight hours.

Reply
Friend of CR4

Join Date: Dec 2004
Posts: 1995
Good Answers: 35
#4

Answer Per Specs & Techs 4/12/05

04/12/2005 12:39 PM

Answer: He's testing to see if the glasses are polarized or not. If they are, the light coming through the lens he's looking through will brighten and darken as he rotates the glasses. (Light from a blue sky is polarized.) If he had another pair of sunglasses that he knew was polarized, he could rotate a lens of the one he's testing in front of a lens from the known polarized glasses, and if the test pair's lens was polarized he'd see the light coming through lighten and darken as he rotated them. Polarized glasses are very useful for eliminating glare because they tend to eliminate horizontally polarized light, and the light reflected off of a road or another car or even a water surface is strongly horizontally polarized. (This is why fishermen use them - the surface glare is drastically reduced and you can see into the water. Rotate them 90 degrees, however, and just about all you'll see is surface glare!) There are some nice discussions of this at http://www.polarization.com/water/water.html and http://www.howstuffworks.com/sunglass.htm/printabl e.

__________________
Off to take on other challenges. Good luck everybody! See you around the Interwebs.
Reply
Friend of CR4

Join Date: Dec 2004
Posts: 1995
Good Answers: 35
#5

And the answer is...

05/12/2005 2:58 PM

As reported in the 04/12 edition of Specs & Techs from GlobalSpec:

He's testing to see if the glasses are polarized or not. If they are, the light coming through the lens he's looking through will brighten and darken as he rotates the glasses. (Light from a blue sky is polarized.) If he had another pair of sunglasses that he knew was polarized, he could rotate a lens of the one he's testing in front of a lens from the known polarized glasses, and if the test pair's lens was polarized he'd see the light coming through lighten and darken as he rotated them. Polarized glasses are very useful for eliminating glare because they tend to eliminate horizontally polarized light, and the light reflected off of a road or another car or even a water surface is strongly horizontally polarized. (This is why fishermen use them - the surface glare is drastically reduced and you can see into the water. Rotate them 90 degrees, however, and just about all you'll see is surface glare!) There are some nice discussions of this at http://www.polarization.com/water/water.html and http://www.howstuffworks.com/sunglass.htm/printabl e.

__________________
Off to take on other challenges. Good luck everybody! See you around the Interwebs.
Reply
Power-User

Join Date: Feb 2005
Posts: 264
Good Answers: 2
#6
In reply to #5

Re:And the answer is...

06/01/2005 4:04 PM

Just checked this out - rotate the glasses against the blue sky and sure enough, dark to light to dark. Cool. Haven't yet checked out the Babe Winkerman effect of being able to see that prize fish (or any fish) through the surface of the water.

Reply
Reply to Blog Entry 6 comments
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.
Copy to Clipboard

Users who posted comments:

Bayes (1); BRodda (1); Chris Leonard (2); Paddy O'Flanigan (2)

Previous in Blog: Wagon Wheels: Newsletter Challenge (03/22/05)   Next in Blog: Mirror Image: Newsletter Challenge (04/12/05)

Advertisement