Touch But Can't See
Science brain teasers require understanding of the physical or biological world and the laws that govern it.
What is solid and not translucent which you can touch with your finger but you can't see it in broad daylight, even through a mirror?
HintIf you're smart enough, you already saw it!
The mirror. Or to be accurate the mirror surface. You don't see it but rather "see" the things reflected by it.
Jun 12, 2002
|That's very clever =)|
Jun 19, 2002
|Sight is the reflection of photons off of a surface into your eye. If the mirror reflects light, even if it appears to be something else, you are actually 'seeing' the mirror. :-)|
Jun 20, 2002
|i would have said glass but glass is a liquid|
Jun 26, 2002
Jun 27, 2002
Jun 29, 2002
|Look at the mirror at a flat angle and you can see the suface.|
Jul 10, 2002
|Soooo Easy but good job!!|
Sep 10, 2002
|My guess was the back of my head. It can't be seen with "a mirror".|
Oct 03, 2002
|Sorry about this, but how about "something deep inside your nostril"?|
Aug 22, 2003
|actually, glass is neither solid nor liquid. it's actually classified as an amorphous solid. but not a solid or a liquid.|
Nov 12, 2003
|That's not what I was taught cattleman. Glass is a supercooled liquid. It flows. Look at very old window panes and the glass has flowed downwards due to gravity making the bottom of the panes thicker than the top. |
Dec 30, 2003
|Cattleman is right, glass is an amorphous solid, (I've taken a whole course on materials, so I know what I am talking about.) A liquid is an incompressible substance that flows due to shear stress. An amorphous solid is just a solid with no crystaline structure. Your are right that glass will flow very slowly due to gravity but it also breaks if too high of a pressure is applied. That is why it is a solid, liquids don't break.|
Jul 03, 2005
|Forget all this amorphous stuff, lets agree its a good riddle okaY? |
Aug 12, 2008
|jimbo, I learned the same thing about glass flowing over time. However, I recently learned that it's not really true as stated.|
The scientific premise regarding amorphous solids is correct, but for glass the time frame is something like 10^32 years. The historical glass panes have imperfections because of the manufacturing proccess.
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