Color-changing Zinc Oxide -- and submit your questions for Ben

Submit your questions for Ben in the comments section for a Q and A session next week.

Heating zinc oxide with a blow torch causes it to turn from a white powder into a golden yellow.  The process reverses when the substance cools back down to room temperature.  The heat drives out some oxygen from the ZnO lattice, cause some locations to have a Zinc metal ion.  This disruption in the lattice is able to absorb more blue and violet light, causing the overall substance to look yellow.

How a Crookes radiometer works

A Crookes radiometer is driven by a thermal gas effect, and not "light pressure" as often thought.  I demonstrate the radiometer in a vacuum chamber and explain its optimal running pressure.
http://en.wikipedia.org/wiki/Crookes_radiometer

Catalytic cigarette lighter

Demonstration of a New Method catalytic cigarette lighter:  The device uses a platinum catalyst to generate heat from methanol vapors, which in turn ignites the vapor.

Tire sealant chemistry and tire pressure monitors

Demonstration of how tire sealant works and how it can damage tire pressure sensors.

Car engine science: Ignition timing, emissions, mixture

I describe how ignition timing and air/fuel mixture affect car engine power, emissions, and driveability.