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: Water Can: Newsletter Challenge (09/20/05)   Next in Blog: Fan Blades: Newsletter Challenge (10/04/05)

Bathroom Mirror: Newsletter Challenge (09/27/05)

Posted September 27, 2005 7:00 AM

The question as it appears in the 09/27 edition of Specs & Techs from GlobalSpec:

Your wife wanders into the bathroom one day and finds you staring intently into the mirror while rotating your head from side to side (about the axis of your nose). Does she:
a) back carefully away while muttering about "crazy engineers"?
b) calmly inform the kids she's having you committed?
c) call your lawyer to trigger your medical power-of-attorney?
d) all of the above?
What are you really doing?

Click here to view previous Challenge Questions.


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

I'm good enough, smart enough, and doggone it....

09/27/2005 10:11 AM

.... making sure that his sideburns are the same length? I really have no idea.

The Feature Creep

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


09/27/2005 11:50 AM

Assuming that the axis means rotating your head from side to side, not keeping your nose in the same position.(Confusing description, everything should rotate on the axis)
I'm assuming that he is looking at how mirrors "reverse" If I turned about a vertical axis the image will be reversed left-to-right, but if I turned about a horizontal axis it would be upside down.

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

Join Date: Sep 2005
Posts: 27

insanity query

09/27/2005 1:45 PM

After thouroughly washing his face, he was tilting his head to remove unwanted water. By tilting his head he was allowing unwanted air to escape from his ear canal.


Join Date: May 2005
Posts: 93
In reply to #3

Re:insanity query

09/27/2005 11:36 PM

Yes, having air in your ears is definately a bad thing :-)

There's no such thing as bad weather....only the wrong clothes!

Join Date: Sep 2005
Posts: 40

Bathroom Mirror

09/27/2005 8:37 PM

Just forget about the bathroom mirror. The guy inside the mirror is look better than you and more hansome. Lucky my bath room does not have any mirror. Otherwise I will looking at myself naked.

Active Contributor

Join Date: Jul 2005
Posts: 24


09/27/2005 11:18 PM

In my case I would most likely be looking at the gray (or dark blond as I like to call it) hair that is slowly taking over. WITH MY BEHAVIOR, my wife would not consider this strange at all but I must be playing with the reversing factor of the mirror


Join Date: Aug 2005
Location: Hemel Hempstead, UK
Posts: 5317
Good Answers: 290

The axis of your nose.

09/28/2005 1:53 AM

Is that a vertical axis? Or horizontal from side to side? Horizontal: front to back? Could this be about the joints in your neck being designed to keep your eyes very steady, even when your body is being jolted about (e.g. running). I wonder if film camera manufacturers have tried to replicate this effect.

We are alone in the universe, or, we are not. Either way it's incredible... Adapted from R. Buckminster Fuller/Arthur C. Clarke
United States - Member - Technical Fields - Education - Hobbies - Hunting - Popular Science - Weaponology -

Join Date: Sep 2005
Location: Texas
Posts: 552
Good Answers: 8


09/28/2005 6:03 AM

The man in the mirror was watching his eyes rotate in thier sockets so that they maintain the same orientation with respect to the horizon while his head rotates about the axis of his nose.

David A Goodman

Join Date: Sep 2005
Posts: 4

Mirror man

09/28/2005 11:44 AM

Obviusly, I was trying to grasp a look of my ear while looking in the opposite direction, c'mon guys we do that all the time.

Friend of CR4

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

And the Answer is....

10/04/2005 11:07 AM

As written in the 10/04 issue of Specs & Techs from GlobalSpec:

You're checking out something called "ocular torsion", a little known but fascinating aspect of eye movement. It turns out that people (and many animals) control their eyes not only up and down and side to side, but also rotationally along the line of sight. This can be seen by getting close to a mirror in a well lit room and rotating your head about the line of sight of one of your eyes, and watching that eye carefully. You'll be able to see that your eye tries to stay "upright" as your head rotates around it (watch the little veins in the white part of your eye, or the flecks in your iris). There are some amazing structures that allow this to happen - muscles like the superior oblique that thread through tiny bone loops like the trochlea. Check out some pretty amazing machinery at these sites:

There is also a pretty cool eye simulator, which lets you disable muscles and muscle combinations, at:

Off to take on other challenges. Good luck everybody! See you around the Interwebs.
Reply to Blog Entry 10 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 (1); DAG (1); Dazed and confused (1); edrosol (1); Hammer (1); Randall (1); Simon (1); Stupott (1)

Previous in Blog: Water Can: Newsletter Challenge (09/20/05)   Next in Blog: Fan Blades: Newsletter Challenge (10/04/05)
You might be interested in: Mirror Mounts, Over-the-Side Heaters