Thursday, November 22, 2012

The Pie in Pyrex

I was reading an article in the Fall2012/Winter2013 issue of "Chemical Heritage" (R. Blaszczyk, Cooking with Glass) about Pyrex bakeware.  Apparently when Corning developed borosilicate ovenware, the first dish produced was a pie plate.  The names considered for the glass were thus Pie-Rite or Py-Right, but then it was changed to Pyrex in 1915 (to rhyme with Nonex, another brand of Corning glass).  Seems appropriate to mention pie on Thanksgiving!  Hope yours is good.

Sunday, November 18, 2012

Starch-containing packing peanuts

Adding water to starch-based packing peanuts begins to dissolve them (conventional polystyrene peanuts are not soluble in water).  If just a LITLLE water is added to the peanuts, only their edges dissolve and they beome sticky.  The sticky peanuts can be then stacked into larger structures.  Colored versions of these sorts of packing peanuts are marketed as "Nuudles".  This demonstration illustrates concepts of like dissolves like, solvent welding, and recyclability of these starch-containing polymers.

Saturday, November 17, 2012

Hydrogen Balloon Fail

I was doing a demo show yesterday, and when my helper attempted to detonate a balloon containing hydrogen and oxygen gas with a lit candle on a stick, the ballon simply popped rather than detonating.  This has happened a handful of time, typically with pure hydrogen in the balloons rather than a hydrogen-oxygen mix.  What I think is happening is that when the candle flame approaches the balloon too slowly, its heat weakens the balloon and causes it to fail.  The gases are then released in such a way that they do not detonate in contact with the frame.

Sunday, November 11, 2012

Fake Frost and Window Crystals


Saw this fake frost on the store windows at a Bass Pro Shop today.  I do not know how it was made, but it shows pretty crystal patterns.  For comparison, the van windows have real frost.  One can saturate water with Epsom salt (magnesium sulfate) and paint the solution on dark-colored paper.  When the water on the paper dries, the white salt crystals look like frost. When I was a graduate student some twenty years ago, I would occasionally work with organic compounds that melted at temperatures not far above room temperature.  Sometimes a flask with a film of this melted liquid would cool in my hands.  As the film solidified, pretty crystal stars would form along the walls of the flask.  This was always fun to see.  Update on 6-4-13:  today one of my kids got some Crayola Crystal Effects Window Markers.  When the marker ink dries it makes pretty crystal stars.