219
CH 40  MEASURING
LIQUID VOLUME
 The Basic Facts:
fluid ounces (fl oz)
cups (c)
pints (pt)
quarts (qt)
gallons (gal)
8 fl oz = 1 c
2 c = 1 pt
2 pt = 1 qt
4 qt = 1 gal
The word gallon comes from the Latin
word galleta, meaning
“bucket.” And the term
cup comes from the
Latin word cupa,
meaning “tub.”
Here are some conversion factors that we will need in the homework:
1 gal
4 qt
1 qt
2 pt
2c
1 pt
8 fl oz
1c
Remember that each fraction is a conversion factor because the
numerator and the denominator are equal to each other (for
example, 1 gal = 4 qt). This, of course, means that each conversion
factor is ultimately equal to 1.
To help you understand that weight and volume are
completely different concepts, consider
that a volleyball and a bowling ball have
about the same volume (they’re about the
same size), but they certainly do not have the same weight.
Ch 40  Measuring
Liquid Volume
220
 Conversion Examples:
EXAMPLE 1:
Convert 100 cups to quarts.
Solution: Cups are smaller than quarts, so we expect that 100
cups will produce a smaller number of quarts. Using the
appropriate conversion factors, we proceed as follows:
1 pt
100 c
1 qt


= 100 qt = 25 qt
1
4
2c
2 pt
EXAMPLE 2:
Convert 3.4 gallons to fluid ounces.
Solution: Gallons are big compared to fluid ounces, so we
expect that 3.4 gallons will convert to a whole lot of fluid ounces.
3.4 gal
2 pt
4 qt
2c
8 fl oz




= 435.2 fl oz
1
1 qt
1 gal
1 pt
1c
Homework
Convert and round to the nearest hundredth, using a calculator if you like:
1.
7.1 qt to pt
2.
8.8 pt to c
3.
5.5 gal to c
4.
6.7 gal to qt
5.
24 c to gal
6.
68 fl oz to pt
7.
33 c to fl oz
8.
2.7 qt to c
9.
0.9 qt to fl oz
10.
6.6 gal to pt
11.
0.7 gal to fl oz
12.
71 pt to qt
13.
1.2 pt to fl oz
14.
4.9 c to pt
15.
5.2 pt to c
16.
34 fl oz to c
17.
407 pt to qt
18.
3.4 qt to gal
19.
55 c to fl oz
20.
0.6 gal to fl oz
21.
60 fl oz to pt
22.
8.8 gal to qt
23.
2.8 c to pt
24.
7.5 qt to c
Ch 40  Measuring
Liquid Volume
221
25.
0.9 qt to fl oz
26.
484 pt to gal
27.
9.5 gal to c
28.
1.9 pt to fl oz
29.
8.8 gal to pt
30.
3.7 qt to pt
31.
2.5 gal to pt
32.
117 pt to qt
33.
2.3 c to pt
34.
4.1 gal to c
35.
4.5 qt to gal
36.
2.8 c to qt
Solutions
1.
14.2 pt
2.
17.6 c
3.
88 c
4.
26.8 qt
5.
1.5 gal
6.
4.25 pt
7.
264 fl oz
8.
10.8 c
9.
28.8 fl oz
10.
52.8 pt
11.
89.6 fl oz
12.
35.5 qt
13.
19.2 fl oz
14.
2.45 pt
15.
10.4 c
16.
4.25 c
17.
203.5 qt
18.
0.85 gal
19.
440 fl oz
20.
76.8 fl oz
21.
3.75 pt
22.
35.2 qt
23.
1.4 pt
24.
30 c
25.
28.8 fl oz
26.
60.5 gal
27.
152 c
28.
30.4 fl oz
29.
70.4 pt
30.
7.4 pt
31.
20 pt
32.
58.5 qt
33.
1.15 pt
34.
65.6 c
35.
1.125 gal
36.
0.7 qt
Ch 40  Measuring
Liquid Volume
222
Ounces vs Fluid Ounces
This can be a very confusing issue. Although they
both have “ounces” in their name, they’re completely
unrelated. The ounce is a unit of weight, while the
fluid ounce is a unit of volume.
First, a chemistry fact: The element mercury, Hg, is a
silvery liquid at room temperature, and it's dense
enough that a brick will actually float in it  Hg is very
heavy.
Now consider a mayonnaise jar that has a volume of
32 fluid ounces (one quart). If that mayonnaise jar is
filled with water, the water has a weight of about
2.1 pounds. But if the jar is filled with mercury, the
mercury weighs about 27 pounds -- same volume
(32 fl oz), but totally different weights. To really bring
this point home, if the jar is filled with cotton candy,
the contents will weigh a couple of ounces. And if
the jar is filled with material from the center of our
Sun, the contents will weigh as much as the entire
Earth!
In short: A quart of water, a quart of mercury, a
quart of cotton candy, and a quart of material from
the Sun have exactly the same volume (32 fl oz) but
drastically different weights.
The bottom line is this: If someone tells you that he
is holding, for instance, one cup (8 fl oz) of material
and asks how much the material weighs, you must
answer, “It depends on what the material is”; do NOT
answer “8 oz.”
Ch 40  Measuring
Liquid Volume