Thunder and Lightning

Anyone with small children has experienced the middle of the night takeover of Mommy and Daddy's bed.  We haven't had rain here in awhile, so I wasn't used to it, but a couple of nights ago at 4:30 AM I hear the pitter patter of small feet, followed by a small body wedging its way between Mommy and Daddy in the bed.  Sure enough, there's a thunderstorm with some loud thunder taking place outside.  This is followed by several minutes of a small leg kicking and pushing me as someone tries to get comfortable.  In the end, I usually give up and take my pillow to the couch.  :-)

RonAlmog [CC BY (https://creativecommons.org/licenses/by/2.0)]

I'm at a loss as to what to tell my daughter during thunderstorms.  A simple "it's just thunder" doesn't calm her down at all and why should it?  It's this very loud boom happening for no reason at all to her.  Me simply saying it's just thunder does nothing to help her understand why thunder occurs.  Then again, telling her the real reason for thunder isn't going to help either.  What 5 year old is going to understand "don't worry, thunder is just the result of lightning super heating the air causing it to rapidly expand, pushing against other air particles and starting a vibration that we hear as thunder"?  And I'm definitely not making something up to make her feel better.  Making up an explanation for thunder that is not true will only hurt her education farther down the road.

So I have no clue on this one.  I can tell her what causes lightning.  I can explain to her why there's thunder, but I can't make her feel better when thunder occurs except to hold her tight and tell her that everything will be okay.  Of course, sometimes that's the duty of a Dad, to hold his little girl tight and tell her that everything will be okay.