If i remember correctly from chemistry class the stability of an elements electron configuration does not directly impact its specific heat capacity. What does is the way the atoms are aligned. For instance water has a very high specific heat because of the polarity caused by hydrogen and oxygen...
I also just received this kit yesterday and had it assembled and functioning within 20 minutes. Did you make sure that before connecting the laser diode you put the LED on the driver and set the current with the LED running? The LED brightness will not appear to change. If you didn't that is...