The lava lamp was designed in the 1960s by Edward Craven Walker, an engineer who perfected this lamp and began what would become a cultural icon. There are several reasons that your lava lamp may not work -- many are user errors. Gentle care of the lava lamp should keep it working for years.
Often times, the blob at the bottom may not be working correctly. It could be simply sitting at the bottom and not floating up the way it should. The bulb could be burnt out and the lamp is not getting hot enough, which will cause the blob to cease working.
A Shaken Lamp
If the lamp has been shaken, it may not work or it may become cloudy. This can become a permanent problem, as the damage might not be able to be fixed. Allowing the lap to cool down and then turn it back on in short bursts may solve the problem.
Ther Right Temperature
Placing the lava lamp near a heater or air conditioner will affect the temperature of the lamp and the floating wax blob may not work properly. The lamp should be operating from 20 degrees Celsius to 22.2 degrees Celsius.