How In The World Do These Touch Activated Lamps Work?!?

[HiTek21]

I cannot figure out how these touch lamps work! It only works when skin touches it. I tried touching it with metal objects, rubber, plastic etc.. none work Does anyone know how it works???

 

[tcsenter]

How Stuff Works

 

[snooker]

I believe it has to do with the heat you generate. Try putting something hot to it. I bet it will work.

My own theory though so it may not

 

[cressida]

I think it's an open circuit and when you touch it, your body has some resistance and the circuit then becomes closed circuit. I dunno, just saying gibberish.