Meteor Impact Demo Modifications

Years ago I learned a meteor impact demo from NASA.  In that demo, a layer of dark colored powder is placed over a layer of light colored powder.  A rock or marble "meteor" is dropped into the powder, which splashes the light colored powder up over the dark powder and makes ray patterns like meteor impacts on the moon (terrestrial impacts, like the one in Odessa, Texas, also show evidence of rock layers being bent up and over each other).  This is a fun demo to do, but with powdered layers it is hard to show the demo to a large audience, because you cannot easily tilt the layers to show the spectators without the layers collapsing.  I have been working on various approaches to solving this problem, and recently came up with using a dark cloth (rather than a dark powder layer) over a layer of light-colored flour.  The marble "meteor"cannot penetrate the cloth, so a hole must be made in the cloth.  To guide the marble to the fabric hole, it is dropped down a tube rather than simply through the air.  The tube (a plastic tube used to cover fluorescent light bulbs) can be held vertically or at an angle to show the effects of different impact angles. The flour splashed up from the hole fans out on the fabric.  The powder is held by the roughness of the fabric sufficiently well that the fabric can be carefully lifted up, but also loosely enough that the flour can be shaken out of the fabric to repeat the demonstration.  Thanks to my daughter Katie for helping with the demonstration.

A chemistry poem for Robert Burns Day

From the Journal of Chemical Education, 2007, vol. 84,  p.605.  More information about the poem is in the article itself.

This poem’s a tribute to Robert Burns

That praises Scottish chemists and their works in four turns.

I hope that you’ve all lowered the bar enough,

I’m a chem teacher, not a poet, but you might learn some stuff.

Joseph Black discovered carbon dioxide.

Without this gas our plants would have died.

Produced when carbon compounds burn,

Too much in the air is a global warming concern.

Black found latent heat would suffice

To explain boiling of water and melting of ice.

James Dewar developed his namesake flask

And for liquid gases it was up to the task.

It’s used today in your Thermos bottle…

…Your eyes are glazing over, so I won’t dawdle.

If I had to choose, if I had to guess,

I think Sir William Ramsay was among the best.

He had English colleagues, which isn’t so wrong.

We can be quite productive when we all get along.

Argon, neon, and others with like labels,

He added noble gases to our periodic tables.

Scottish pride likely hit new highs

When in 1904 he earned a Nobel Prize.

Finally there was Thomas Graham (not of cracker fame)

Who developed the law that now bears his name,

Which says that the rates of effusion of gases

Are inversely proportional to the square roots of their molar masses.

(We even cover this in our General Chemistry classes!)

We have students use this law in gas analysis,

But neglect to mention his gains with dialysis.

Over one million lives have been spared in this way.

His use of the word “colloid” remains to this day.

The word (meaning “glue-like”) can describe gel behavior

            Nanotechnology helps keep colloids in favor.

Four Scottish chemists whose fame involved gases.

Be thankful this poem is shorter than my classes!

Speaking of gases, if you think my air’s gone too far,

Note I wrote much of this in a car!

Ken Kolb's Birthday

Last night I attended an 85th birthday celebration for Ken Kolb, a professor at Bradley University.  He and his late wife, Doris, are big names in the area of chemistry education and both had a tremendous career at Bradley.  When I first interviewed for my job at Bradley, an associate where I was working at the University of Wisconsin-Madison said to me "You're going to the house of Kolb!"

A favorite chemistry poem

I think I saw this poem on a lab door a couple decades ago in graduate school and finally found it again today.  It is a parody of 'Twas the Night Before Christmas" and is credited to John F. Hansen of the St. Louis section of the American Chemical Society in 1978.

‘Twas the night to make crystals, and all through the ‘hood,
Compounds were reacting as I’d hoped that they would.
The hood door I’d closed with the greatest of care,
To keep noxious vapors from fouling the air.

The reflux condenser was hooked to the tap,
And the high vacuum pump had a freshly filled trap.
I patiently waited to finish my task,
While boiling chips merrily danced in the flask.

Then from the pump there arose such a clatter,
That I sprang from my chair to see what was the matter.
Away to the fume hood! Up with the door!
And half of my product foamed out on the floor.

Then what to my watering eyes should appear,
But a viscous black oil which had once been so clear.
I turned the pump off in a terrible rush,
And the oil that sucked back filled the line up with mush.

The ether boiled out of the flask with a splash,
And hitting the mantle, went up with a flash!
My nose turned quite ruddy, my eyebrows went bare,
The blast had singed off nearly half of my hair.

I shut the hood door with a violent wrench,
As acid burned holes in the floor and the bench.
I flushed it with water, and to my dismay,
Found sodium hydride had spilled into the fray.

And then the fire got way out of hand,
I managed to quench it with buckets of sand.
With aqueous base I diluted the crud,
Then shoveled up seven big buckets of mud.

I extracted the slurry again and again
With ether and then with dichloromethane.
Chormatographic techniques were applied
Several times ’til the product was purified.

I finally viewed with a satisfied smile,
One half a gram in a shiny new vial.
I mailed the yield report to my boss,
Ninety percent (allowing for loss).

“Good work,” said the boss in the answering mail,
“Use same condition on a preparative scale.”

Orange Peel Attack on Plastic Knife

A transparent plastic knife (I think comprised of polystyrene) shows sign of attack from the oil in the peel of an orange. This is a simple way to show a nonpolar solid partially solubilized by a nonpolar solvent.

Cereal Clusters

My younger daughter started finding clusters in her chocolate-flavored puffy round cereal today.  We did not keep rigorous records, but as the picture suggests the dimers were more common than the trimers, which were in turn more common than the tetramer (this tetrahedron was the only one we saw).  This brings to mind some different ideas.  For example it might make a good science fair project to survey the cluster populations and show that the bigger the cluster, the more rare it becomes.  This in turn leads me to think about probabilities of bimolecular and termolecular collisions in kinetics and wonder if some connection can be made to these clusters.  Well, at the very least, the clusters remind me of groups of hybridized orbitals associated with an atom.  The dimers remind me of two sp hybridized orbitals, the trimers remind me of three sp2 hybridized orbitals, and the tetramers remind me of four sp3 hybidized orbitals.