Measurement
& the Metric
System
Monday, August 3rd, 2015
Measurement
• The dimensions, capacity, or amount of
something
– Time
– Temperature
– Length
– Volume
– Mass
Measurement Definitions
Mass - the amount of matter
Volume - the 3D space matter occupies
Temperature - the average heat of the
particles in matter
Length - the longest linear dimension of
matter
Standards of Measurement
When we measure, we use a measuring tool
to compare some dimension (amount) of an
object to a standard, an exact quantity that
is agreed upon for comparison.
The Metric System
• Based on multiples of ten
• Uses “base units”
– Time: second (s)
– Temperature: Kelvin (K)
– Length: meter (m)
– Volume: liter (L)
– Mass: gram (g)
All of these are
directly measured
Learning Check
Identify the measurement in metric units.
1. John’s height is
A) 1.5 yards B) 6 feet
C) 2 meters
2. The volume of saline in the IV bottle is
A) 1 liters
B) 1 quart
C) 2 pints
3. The mass of a lemon is
A) 12 ounces B) 145 grams C) 0.6 lbs
Learning Check
Identify the measurement in metric units.
1. John’s height is
A) 1.5 yards B) 6 feet
C) 2 meters
2. The volume of saline in the IV bottle is
A) 1 liters
B) 1 quart
C) 2 pints
3. The mass of a lemon is
A) 12 ounces B) 145 grams C) 0.6 lbs
The Prefixes
• The metric system uses “prefixes” to
modify the base units.
• For example, a centimeter is 0.01 of a
meter. 1 cm = 0.01 meters
1. Length
a. The distance from one point to another point.
b. Base unit is the meter (m).
c. Tool is the metric ruler.
2. Volume
a. The amount of space a substance occupies.
b. Base unit is the liter (L).
c. Tool is the graduated cylinder.
3. Mass
a. The amount of matter in a substance.
b. Base unit - gram (g).
c. Tool is the balance (triple beam or electronic)
Using the Tools
A. 65 mL
B. 67.5 mL
C. 75 mL
D. 50 mL
E. 50 mL
A. 48 mL
B. 45 mL
C. 38 mL
D. 27 mL
E. 18 mL
F. 7 mL
Significant Figures and DOUBT
• Always go one digit past where the
measuring tool is incremented for.
This is known as reasonable doubt.
For example:
The Importance of Units
NASA: Human error caused loss of the Mars
Orbiter on November 10, 1999
WASHINGTON (AP) -- Failure to convert English
measures to metric values caused the loss of the
$125,000,000 Mars Climate Orbiter, a spacecraft that
smashed into the planet instead of reaching a safe
orbit, a NASA investigation concluded
``The root cause of the loss of the spacecraft was a
failed translation of English units into metric units ..."
said Arthus Stephenson, chairman of the investigation
board.
You are driving to find a friend’s house and get lost Google Maps is not working!!! You stop and ask a
stranger walking his dog for directions, and he seems to
know where you want to go.
“ Take a left at the next stoplight, and then go five.”
Complete the sentence on your own without consulting
anyone else.
Take a left at the next stoplight, and then go five
_________________________.
OK... Yes units are important! But what do you do if
you are unfamiliar with the unit of measurement?
It helps if you can relate it to something else...
Units of measurement can be related through the use of an
equivalency, or conversion factor.
An equivalency is a mathematical statement of the
relationship between two different units of
measurement.
ex) 1 m = 100 cm
A conversion factor is a rearranged form of the equality
used to convert one unit of measurement to the other
by simple multiplication.