Squirrel Girl wrote:
Hydrostatic Weighing
This is just a fancy way of saying underwater weighing. Like DEXA, this test is one of the more accurate ones. How it works:
    * You sit on a scale inside a tank of water and blow out as much air as you can
    * You are dunked underwater, where you blow out even more air
    * Since fat is lighter than water, the more fat you have, the more you'll float. The scale measures underwater weight to figure out body density.
    * The margin of error is around 2-3%, but the accuracy depends on the amount of air you expel. You have to blow it ALL out or it won't be as accurate.
    * This is a difficult way to measure body fat since it can be uncomfortable and even scary to be dunked underwater with no air in the old lungs.
Could I recommend an easier alternative? Borrowing the logic from another source...
Quote:
  BEDEMIR:  Tell me, what do you do with witches?
  VILLAGER #2:  Burn!
  CROWD:  Burn, burn them up!
  BEDEMIR:  And what do you burn apart from witches?
  VILLAGER #1:  More witches!
  VILLAGER #2:  Wood!
  BEDEMIR:  So, why do witches burn?
      [pause]
  VILLAGER #3:  B--... 'cause they're made of wood...?
  BEDEMIR:  Good!
  CROWD:  Oh yeah, yeah...
  BEDEMIR:  So, how do we tell whether she is made of wood?
  VILLAGER #1:  Build a bridge out of her.
  BEDEMIR:  Aah, but can you not also build bridges out of stone?
  VILLAGER #2:  Oh, yeah.
  BEDEMIR:  Does wood sink in water?
  VILLAGER #1:  No, no.
  VILLAGER #2:  It floats!  It floats!
  VILLAGER #1:  Throw her into the pond!
  CROWD:  The pond!
  BEDEMIR:  What also floats in water?
  VILLAGER #1:  Bread!
  VILLAGER #2:  Apples!
  VILLAGER #3:  Very small rocks!
  VILLAGER #1:  Cider!
  VILLAGER #2:  Great gravy!
  VILLAGER #1:  Cherries!
  VILLAGER #2:  Mud!
  VILLAGER #3:  Churches -- churches!
  VILLAGER #2:  Lead -- lead!
  ARTHUR:  A duck.
  CROWD:  Oooh.
  BEDEMIR:  Exactly!  So, logically...,
  VILLAGER #1:  If... she.. weighs the same as a duck, she's made of wood.
If fat floats, and wood floats then logically the higher the difference in weight between you and a duck the skinnier you are. Anyone know how much a duck weighs on average?
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Quote:
In comic strips the person on the left always speaks first. - George Carlin