# Lesson 2 Notes - Bloomsburg Area School District ```1. An inch, a mile, a pound and
a gallon are standard units of
measurement.
2. A system of measurement that
is based on units of 10 is the
metric system.
3. An object’s width is the
number of units that fit across.
square units, such as square
centimeters, is a measurement of
area.
5. The comparison of an object’s
mass to its volume describes
density.
6. To find the density of an object
divide its mass by its volume.
7. An object floats when its
density is less than the density of
the liquid or gas into which it is
placed.
8. Heated air becomes less dense;
cooler, denser air forces it upward.
9. The density of water is 1
g/cm&sup3; while the density of cork is
0.24 g/cm&sup3;.
10. The density of an object
affects its buoyancy.
11. The measure of the pull of
gravity from a planet on the mass
of an object describes an object’s
weight.
12. Ounces and pounds are the
English units for weight, and the
newton (N) is the metric unit for
weight.
13. An object’s weight changes
with gravity, but its mass stays
the same.
300 pounds on Earth!
50 pounds on the moon!
14. Do you think that if a
marshmallow and a marble are
the same size, they would have
the same mass, density,
buoyancy, or volume?
14. I think they would have the
same volume. If they’re the
same size, they take up the same
space. The marble has more
mass and more density than the
marshmallow. Also, I know a
marble does not have buoyancy.
```