Friday, October 7, 2011

Oooo That Smell…

This sign was posted by my physics colleague today.

I really don’t try to make my colleagues hate me, I swear.   

Today we did the classic Iron and Sulfur experiment.  This is a full assault to the senses, most notable the olfactory.  In this experiment we compare the physical properties of iron, sulfur, and a mixture of iron and sulfur.  Then we put the mixture in a test tube and heat it vigorously, which causes a chemical reaction between the two elements. 
The iron and sulfur reaction is very exciting to watch.
The reaction takes a few minutes to get going.  At first, the reaction mixture smolders a bit; some of the sulfur comes off as a gas, and condenses on the sides of the test tube as a red and yellow coating.  Then a red glow begins to form in the test tube, which spreads until it looks like lava inside the test tube.  It actually produces enough heat to sustain the molten-looking reaction for several seconds without the Bunsen burner flame.  

Notice the puff of sulfur coming out of the test tube.
Plunging the test tube in water is all part of the fun.

 For the finale, the students plunge the test tube into cold water.  The reaction mixture gives off a big puff of steam, accompanied by a loud hissing sound, and some of the water boils around the black product pellet.  The hot glass cracks, releasing their sample of iron sulfide into the beaker of water.  At this point, everyone in the room is too excited about the flames, the molten product, and the breaking glass to notice the strong sulfur smell.  Of course, the students in the neighboring physics and biology labs are not amused when the odor works it way throughout the building.  

 Sorry guys, but this one is totally worth it!