Objective: To examine the weight of water in various containers.
The weight of a given container of water is equal to the
density of water times the volume of water. The volume units
in the density of water description need to be the same as
in the volume of the container.
Since there are 8 pints in a gallon, the weight of one pint
of water is roughly 1 pound. If you drink 4 pints, you add
about 4 pounds to your weight.
The weight of water is equal to the density times the volume.
If we assume the density of water is 62.4 pounds per cubic
foot, the following calculator gives the weight of a selected
volume of water. First, select the units you want to use from
the pull down menus. Then enter the volume and the calculator
will give the total weight.
Experiment - Weight of your hand
How can you measure the approximate weight of your hand?
One way is to use a container filled with water and standing
on a scale. Select the hand and arm in the figure and place
it under the water up to the wrist. The scale reading gives
the approximate weight of the hand in the water.
Why this works. The density of the human body is roughly
that of water. When you place the hand in the water the volume
of water displaced is that of the hand. The weight of the
volume of water displaced (the volume of the hand) is equal
to the buoyancy force. The buoyancy force pushes up on the
arm and also down on the water and scale. The weight shown
on the scale is the buoyancy force, and approximately the
weight of the hand.
