Volume
Volume
Definition & Units
Volume is the amount of space
something takes up.
Think back to your lesson about
the phases of matter. One of the
characteristics of both solids and
liquids is that they have their own
volume. Gases have the volume
of the container they are in.
There are two units of volume:
milliliters (mL) and centimeters
cubed (cm3).
Measuring cup clip art licensed
from the Clip Art Gallery on
DiscoverySchool.com
Volume
Measuring Cubed Solids
To find the volume a cubed or
rectangular solid multiply the
length, width, and height
(LxWxH).
The units for cubed solids are
cm3. Make sure when you
measure the length, width and
height of an object that you do it
in centimeters and not inches.
Volume
Measuring Liquids
To find the volume of a liquid, all
you have to do is a straight
measurement - pour the liquid into
a container that shows the
measurements. The liquid
measuring cups that your mom
uses in the kitchen measure liquid
volume. In science, the best way to
measure liquid is with a graduated
cylinder or a beaker.
When measuring liquid volume,
use milliliters (mL) as the units.
Volume
Meniscus
When you measure volume
with a graduated cylinder, you
have to watch out for the
meniscus. A meniscus is a dip
in the graduated cylinder
caused by water sticking to
the sides of the graduated
cylinder. Always read the
volume of the liquid at the
bottom of the meniscus.
Meniscus
Image from Chem Pages
Volume
Measuring Irregular Solids
How would you find the volume of
this rock or these nails? There are
too many sides of the rock to
measure with a ruler, and the nail
changes size as you get closer to
the tip.
The best way to measure these
objects would be to use a
measuring method called water
displacement.
Volume
Water Displacement
How Water Displacement Works:
1. Fill a graduated cylinder to a known
measurement.
2. Drop the object being measured into
the graduated cylinder.
3. Look at the new volume.
4. Calculate the difference between the
first and second volume. The difference
equals the volume of the object.
Or…
Volume
Water Displacement
1. Fill a container with a spout (like a
liquid measuring cup) full to almost
overflowing with water.
2. Place another container beneath the
spout to catch the water.
3. Place the object to be measured in
the container with water. Water should
spill out into the catching container.
4. Measure the water that spilled into
the catching container. The volume of
the overflow water will equal the volume
of the object.
Overflow water spills
into the “catching
container”.
Measuring cup filled
to almost overflowing.
Overflow water measured in
a graduated cylinder to find
the volume of the object.
Measuring cup clip art licensed from the
Clip Art Gallery on DiscoverySchool.com