Planet gravity bottles at the Challenger Learning Center

Earlier this week, one of my classes visited the Challenger Learning Center at Heartland Community College in Normal, IL.  As noted on their website (http://challengerlearningcenter.com/):  

“The Challenger Learning Center provides simulated space missions to central Illinois schools of K-12 students. Kindergarten through fourth grade students take on the roles of astronauts, scientists, and engineers during their MICRONAUT mission. Students in grades fifth through eighth become the flight controllers and astronauts during their SCHOOL mission to Rendezvous with a Comet, or take a Voyage to Mars. Ninth through twelfth grade students not only become the flight controllers and astronauts during their HIGH SCHOOL mission, but also lead their mission, Operation: Planet Rescue.”  The place is pretty awesome, though the cost of the missions might require some creative funding on the part of schools.  Since we were a group of teachers, we got a free tour after hours (though we did not run any missions).  One demo that a lot of us liked were 20 oz. Pepsi bottles that were emptied, refilled with sand and metal shot to alter their weights, and then relabeled to explain what the weights of the bottles would be on various planets.  These were developed by the director of the center.

Ammonium nitrate in the news and over the years

Ammonium nitrate finds its way into any good discussion of nitrogen chemistry.  This compound, used as a fertilizer in many cases, also can be used as an explosive.  A former student of mine had a parent that worked at a company that mixed ammonium nitrate and oil to produce a blasting material for construction purposes. The oil adds more reducing power to the redox reactions involved in the explosions, increasing their potency. Unfortunately, many terrorists have produced a similar mixture and used it in events such as the World Trade Center bombing in 1993 and the Alfred P. Murrah federal building bombing in Oklahoma City in 1995.  Ammonium nitrate can explode to do plenty of damage without oil, too.  One example is the  explosion at the fertilizer plant in West, TX (which is located in the eastern half of Texas), see:  http://www.cnn.com/2013/04/19/us/texas-explosion/index.html?hpt=hp_inthenews.  Previous to that there was an explosion at a fertilizer plant in France in 2001.  And of course there is the Texas City disaster in 1947, in which two ships loaded with ammonium nitrate exploded and did extensive damage.  I visited Texas City in 2011 and stopped by their city museum and other sites.  They featured, among other exhibits, information about the disaster.  Some pictures of that visit are featured in this post.

Heterogeneous Catalysis with the AOSept System

I wanted a small demo of heterogeneous catalysis for class today, and found a package featuring the AOSept contact lens cleaning system in my demo area.   In this system,

the contact lenses are placed in a cleaning solution that contains hydrogen peroxide.  To help keep the peroxide from getting into person's eyes, the vial containing the peroxide solution and the contact lenses also contains a platinum-coated disk, which catalytically decomposes the hydrogen peroxide into oxygen gas and water.  After about 6 hours, the contacts are clean and the peroxide has decomposed.  The picture shows oxygen bubbles in the vial that I passed around my class.  It should be noted that there is a gas vent in the top of the vial and therefore the vial should be kept upright to prevent spills.

Space Shuttle Tile

Years ago, NASA gave away space shuttle tiles to educational institutions for demonstration purposes. One thing that amazed me when I first picked one up is how lightweight

it was - but I guess that makes sense if they needed to be launched into space. We still use them as props at outreach events.  I have included an optical micrograph of the glass fibers in the tile structure.  The black marks at the bottom of the picture are one millimeter apart.