One of my lava lamps has gone strange. The purple lava isn't flowing properly. It's sticking to the sides. It's flowing up the walls and not fully liquifying. Furthermore, when the lamp is off all the lava isn't settling in the bottom. Little spots of it are sticking near the top, on the sides, little round spots of small substance. Is the lava going bad or is the light bulb a bit cool? Neither? Other? Where is Mr. Wizard when you need him?