Physics help about density!

Question

Hi! If we were to measure our body parts' densities, would the hand be more dense than the forearm? why?

Answer 1

Hi Rin F.,

An outstanding problem! So, you would have to estimate the composition of the various body parts. Muscle has a particular characteristic density, as do adipose tissue and other layers of the skin, cartilage, and various types of osseous (bone) tissue. There would be contributions from the blood contained therein, also (unless you had measured values from tissue including that). You can probably neglect nervous tissue as a minor player.

You might start by approximating the bones as cylinders of diameter as per X-ray, and calculating their proportional volume. For a hand and arm volume, you could measure directly by water dispacement. But that won't separate out the skin from the muscle. And the skin thickness varies with (anatomical) location.

--Cheers, --Mr. d.