I'm voting with Mr. Mann, so that's 2 to 1.
Your mass and your volume will be the same if
your lung volume is the same (and it's the same
day, so you haven't gained or lost weight!).
I think you could take a deep breath and relax
into a cannonball float quite comfortably. How
easy do you find it to float on your front vs your
back? Your actual surface area is the same
regardless of your position, since you're not
going to cannonball tightly enough to actually
include or exclude any water or air with your
body, as compared with flat floating. I think
your buoyancy just relates to an amount of
water displaced, based on your mass and
volume, so that shouldn't change. But you can ask
Mr. Mann about that - I know more biology and
chemistry than physics. Based on my experience
with floating, though, I think the sensation feels
quite different for the 3 floats; and this is
probably the reason for your different
Give my greetings to Mr. Mann and tell him I
think teaching high school science is a really
valuable job. Also - check out 'buoyancy' and
'floating' and such on www.google.com - I think
everyone floats, but maybe some people have too
little fat, except in their heads, where our
brains are full of fat. And try some simple
There are, of course, clay boats and foil boats,
where you can displace enough water to make heavy
things float, but I don't think that's what's
happening with you.
Let me know if you come up with any convincing
evidence that Mr. Mann and I are wrong!
Click Here to return to the search form.