Dough Rise Joke

 I often went to visit an old lady who lived alone.

One afternoon I arrived to find her old-fashioned wireless radio full on.

She was listening to a lecture on Ancient Egypt.

"I didn't know you were interested in ancient history, I said"

"Oh, I'm not listening to it,"she replied, 

"but the valves get just hot enough to make the dough rise in that bowl on top of the set."