Illustrating metal deformation at the atomic level using egg crate cartons

The video shows how you can illustrate metal deformation at the atomic level (with slip planes and dislocations) using egg crate cartons.  Metal deformation using slip planes can also be illustrated with flat paper cutouts with six-fold symmetry.  These paper lattices can be used on an overhead projector for demonstration to an entire class, or they can be constructed and studied on individual bases by students. 
See: K. F. Robinson, P. N. Nguyen, N. Applegren, D. J. Campbell, “Illustrating Close-Packed and Graphite Structures with Paper Snowflake Cutouts” The Chemical Educator, 2007, 12,163-166.

Changes in the Community Solar System

INITIAL POST 8-16-13: With the Lakeview Museum changing to the Riverfront Museum, the position of the "sun" for the Community Solar System had to be changed, and with it, most of the major features of the world's largest complete scale model of the solar system. The model also got bigger - the Earth is now 5" instead of 4" in diameter. On 8-15-13, the Jupiter model was taken down in Olin Hall at Bradley University, because it is now out of scale and out of its orbit, see: http://www.bradley.edu/about/news/article.dot?id=707b0dc1-9ec7-42ee-bb9b-92e0ab49ce08.  I'm a bit sad about that because I used to show that model to campus visitors. Today, my younger daughter and I visited the inner planet models of the solar system, now conveniently located in about a 1.5 mile stretch of riverfront pathway. 10-26-13 UPDATE:  We visited the sun, a circle in the bricks at the Riverfront Museum. 8-3-14 UPDATE: Took Katie to see Jupiter at the Peoria airport.
4-10-16 UPDATE: Saw Pluto at Good's Furniture in Keewanee, IL.

Folded paper "snowflakes" with different symmetries

I like to play with folder paper cutouts and making paper snowflakes.  Recently I have been experimenting with trying to get different symmetries, that is, making snowflakes with different numbers of mirror planes as folds.  The picture below shows the result: objects ranging from one to ten mirror planes. (The first object is a paper heart rather than snowflake since it so obviously has just one mirror plane.)  The hardest folding to figure out was the snowflake with the seven mirror planes. If you closely examine each folded figure I hope you see that I incorporated a number into each pattern that matches the number of mirror planes in each pattern.

Update 2-14-16: Here are snowflakes with eleven and twelve mirror planes.

Simple cold weather gas laws experiment

2 liters of gas at 294 Kelvin becomes about 1.75 liters of gas at 258 Kelvin.

Beilstein Test with Christmas Lights

I have heard over the years about placing old Christmas lights into a campfire to make the flames turn green. This is a variation of the old Beilstein test for halogenated compounds, where copper metal reacts with halogens in a flame to turn the flame green.  In the case of the Christmas lights, the halogens are supplied by the chlorine in the polyvinyl chloride (PVC) insulation and the copper metal is supplied by the electrical wiring.  I tried this with a little bit of Christmas light wiring and the flame from a propane torch.  When the copper wire alone or PVC insulation alone was in the flame there was no green color, but where there was exposed wire near the insulation the flame turned green.

Decomposition of Esters in Old Scented Markers

We have some old scented markers in our Sunday school classroom and I have noticed that in addition to the pleasant fruity and minty smells I noticed that there is a sort of a vinegary smell.  I assume that is due to the esters that produce the scent decomposing to produce carboxylic acids such as acetic acid.  Our department chair has pointed out to me that when he opens a bottle of uncoated aspirin he can briefly smell acetic acid, presumably from decomposition of that ester.

Flashbulbs

Wow, I guess it has been a while since I have added to this blog.  Recently, I found several unused flashbulbs produced by General Electric.  Each bulb contains very fine wire which resistively heats and burns in the oxygen atmosphere of the bulb, producing a bright flash.  Felicia Staiger acquired a scanning electron microscope image and an energy-dispersive X-ray spectrum of the wires.  The spectrum indicated that the wires were comprised of aluminum.