actually “extra bits” meant the boy and girl bits, as this all started with a conversation regarding the weight of a woman’s breast.

FWIW, the (un)educated guesses from my flatmates (both male and female) are between 6 and 20kg for the human head (we Aussies are well endowed of course!) and 0.2 to 1kg for the breast (12C).

Our scientific basis for the breast weight guesses was to go into the kitchen and lift various weights of sugar etc.

I heard a mans head weighs about 8 kilos, or 10 including the helmet. It was on some sort of pseudo-scientific item in a Formula One program. Centrifugal forces and all that.

All of you are wrong. My head which is of average size (7 3/8 is my hat size) weighs 172lbs. I was surprised by how heavy it was but I weighed it three times to be certain (on two scales as well).

I hope you all appreciate the fact that I now have a bump on my head from doing all those head-stands. It hurts. ow. ow.

If you’re interested in the weights, volumes, momemts of inertia, etc. of body parts you might want to look up the proceedings of the Stapp Car Crash Conferences, and at the biometric data assembled at Wright-Patterson Airforce Base. There’s a report by Wilfred Dempster from, I believe, the 1960s, and some later reports from the 1970s. What they did was to measure properties of bodies (circumference of wrist, length of forearm, etc. Non-lethal measurements you can perform on a living human being) of corpses. Then they “dismantled” the corpses and measured the properties of the parts. They describe this in wonderfully gory detail. Accurate, though. They list formulas you can use to calculate the weight of the forearm by measuring the circumference of the wrist, multiplying it by some factor, and adding to another factor times the length of the forearm, say. I could see this making a great party game (“How much do you think your head weighs?”). It’s pretty useful for biomechanics. I used it in my undergraduate thesis.