When you clap, you’re creating what scientists call a “Helmholtz resonator,” which is the same principle that makes sound when you blow across a bottle opening.

Why does thunder sometimes sound like a sharp 'clap' and other times like a long, low rumble? Keep in mind that thunder is a compression, or shock wave...caused when lightning heats the air.

And while some people were kept awake by the thunder clap that accompanies the flashing lights, some people were left wondering why there was no rumbling sound of thunder.