I think thunder is the clouds fighting and bashing eachother and lightning is fire balls from the sun.
A childhood belief about thunder and lightning

others believed things like this
- i always thought it was Grape Balls of Fire instead of Great Balls of Fire— Courtney
- I used to believe that people could fly during thunder and lightning, because I dreamt this once— Minimania
- I was convinced that thunder and lightning could wake up volcanos.— leticia
- i used to believe that when there was thunder and lightning god was playing bowling at a disco— georgia
- Lightning and thunder were produced at the garbage dump.— penny
- My Grama always told me that thunder was just God bowling and the lightning was when he got a strike!— Kim