How do they make the sound of a punch in the movies?

Mattmonger:

Growing up on television and movies, I was continually presented with one man hitting another man in the face with a closed fist. It always had this distinctive noise: a sound somewhere between meaty and metallic, a way-audible PKK! Being a strict, born-and-raised pacifist myself, I've always been curious. Is that the sound a closed fist actually makes at high velocity on a face? And what did foley artists back then use to get that oh-so distinctive noise?

-- J.D. Boucharde, North Park

Man, you've got the elves going at it. A big free-for-all in the family room. Dope slaps! Bitch slaps! Uppercuts! Grandma's hiding in the laundry room. Pa Alice just turned up the TV so he could hear WWF Smackdown over the bedlam. We'll sort it all out in a minute, but in the meantime, what's up with the foley stuff. For those who don't know, the foley artist is the guy/gal who supplies the synchronized sound effects for a movie-- sounds that couldn't be recorded accurately on the set during filming: footsteps, mosquitoes buzzing, kissing, doors closing, fenders crunching, sighs, burps, the rustle of clothes, a match being struck... As much as 80% of any movie might have sound (including dialog) added or altered in post-production. Ya see, real life isn't real enough for the movies; a director can always make it more real than reality.

Seen the TV ad for "The Count of Monte Cristo"? The metallic sword clash sounds were the work of a foley artist. The swords used on the set were most likely plastic. C3PO's footsteps were created by a foley artist wearing a child's wooden skis that sounded like flippers. The sound of horses' hooves is still made the way they did it in the 1930s-- with half coconut shells clomped on some appropriate surface.

As for the classic sound of fist meeting jaw, there are a couple of ways to achieve it. If you're going for a meaty-squishy sound with overtones of a high-pitched smack, hit a frozen head of Romaine lettuce on the edge of a table, then combine that with the sound of a wooden slat being snapped. Cabbage smacked with a hammer also works. Or a boxing glove hitting a phone book. The sound of Homer Simpson getting hit in the gut with a baseball.

Naturally, the sound of a real fist meeting a real face isn't what the foley artist is trying to replicate. Most likely the director wants an exaggerated, shocking sound. So it doesn't really matter what a real punch sounds like. We believe it sounds like it does in the movies. Besides, I couldn't hear the real sound over all the elf screams.