♪ Counting up from ones is fun ♪ One then two is doubled one ♪ Three then four, let's add some more ♪ ♪ Five and six, we're full of tricks ♪ ♪ Seven, eight, then nine and ten ...

If you can count to 10 between seeing the lightning and hearing the thunder, then the flash occurred about 2 miles away. This trick works because light travels much faster than sound.