Expansion of Water as It Freezes

There are lots of demonstrations showing the expansion of water when it freezes (and demonstrating hydrogen bonding and molecular geometry), but the demos do not need to terribly sophisticated.  Here is what happened when I left a full water bottle in a cold car overnight.

Blackbody Radiation with an Incandescent Bulb on a Dimmer Switch

The camera does not show this as well as the eyes, but I thought this incandescent bulb was a good qualitative example of black body radiation.  As I turned the lamp switch from dimmer to brighter, the relative intensities of shorter wavelengths of light increased.  The net result is that the relatively cool dim bulb appeared reddish and the relatively hot bulb appeared yellow or white as more blue light was mixed into the glow.