Metric Units And Conversions (Page 4 of 8) in pdf

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YouTube Conversion Problem 2

YouTube Conversion Problem 3

3.5 Volume by Displacement

The volume of an object can be measured by adding the object to a container holding water and

finding the difference between the two water levels. If a volcanic rock is placed in a beaker

containing 245.8 mL of water and the water level rises to 315.3 mL, what is the volume of the

rock? The answer is found by subtraction. 315.3 mL – 245.8 mL = 69.5 mL.

Let’s mention volume units - a mL is actually the exact same as a centimeter cubed or cm

which is often abbreviated as cc in the medical field. Thus mL = cm

= cc.

3.6 Volume by Calculation

Back in high school you probably learned how to calculate the volume of a rectangular solid, a

sphere, and a cylinder. Do you recall those equations? Can you match the following equations

to a rectangular solid, a sphere, and a cylinder?

1) V = 4/3  r

2) V =  r

3) V = l w h

Well 1) is a sphere, 2) is a cylinder and 3) is a rectangular solid. We will expect you to

remember V = l w h for a rectangular solid.

Example: Calculate the volume of a shoe box measuring 24 cm by 13 cm by 15 cm.

Answer: V = (24 cm)(13 cm)(15 cm) = 4700 cm

Did you say 4680 cm

? Well remember sig fig rules. The answer must have no more significant

digits than the problem which has only 2 sig figs. So we must round to 4700.

3.7 Density

Density:

The amount of mass per unit volume of matter.

Density describes the relative compactness per area of a substance, which is based on the

concentration of mass in a sample. The more atoms squeezed into a given area the denser the

sample. If there is space between the atoms, the sample is not very dense. Density is not weight

alone. Realize that 5 pounds of Styrofoam is heavier than 1 pound of steel, but the steel is still

more dense than foam.

Smith, Clark

GCC CHM 130

Chapter 3: Metric Units and Conversions

page 4

Metric Units And Conversions Page 4