Unit Conversions
Learning Objectives
•Solve unit conversion problems.
•Use dimensional analysis to convert between metric units.
•Determine the meaning of common metric prefixes.
•Use dimensional analysis to convert between metric and non-metric
units.
•Convert from scientific notation to standard number format.
Vocabulary
1.
2.
3.
4.
5.
6.
7.
base unit
cancel
conversion factor
dimensional analysis
metric system
prefix
scientific notation
1. Base unit –
a unit in the metric system on which
other units are based.
> Examples:
meter (m) = length
gram (g) = mass
liter (L) = volume (liquid)
g/cm3 = volume (irregular solid)
second (s) = time
2. Cancel –
to cross out, remove, delete, or
invalidate.
> when identical terms are in the
numerator & denominator, they can be
cancelled: , such as the unit “seconds” in
this equation:
120 seconds •
1 minute
60 seconds
= 2 minutes
3. Conversion factor –
a ratio or fraction = 1 that’s used to
multiply/divide when converting from
unit to another.
> Ex: conversion factor for seconds to
minutes is:
60 seconds
1 minute
4. Dimensional analysis –
a technique in which cancelling units is
used to obtain the correct solution to a
problem.
5. Metric system –
a system of base units & prefixes used in
science
6. Prefix –
word/symbol before a unit that
multiplies that unit by a
power of 10.
Prefix
Symbol
Meaning
kilo-
k
1,000
hecto-
h
100
UNIT
1
deci-
d
1/10
centi-
c
1/100
milli-
m
1/1,000
micro-
μ
1/1,000,000
BASE
7. Scientific notation –
method of writing very large/small
numbers.
> consists of a number between
1 - 10 multiplied by a power of 10.
> EX:
41,600,000
in scientific notation =
4.16 × 107.
Today you will familiarize yourself with common conversion
factors & choose from a range of conversion factor tiles in
order to cancel units and solve a variety of problems.
The investigation contains 4 activities:
•Activity A – use dimensional analysis to solve conversion
problems.
•Activity B – use conversion factors to determine the meaning
of metric system prefixes and solve conversion problems
dealing with two unit conversions.
•Activity C – use conversion factors to convert between metric
and non-metric units.
•Extension – convert numbers into and out of scientific
notation.
Before you begin…
Sara lives in Toronto, Canada, while her cousin Michael lives in
Detroit, Michigan. They like to compare how fast they are
growing up.
1. Sara tells Michael she is 160 centimeters tall, while Michael
says he is 60 inches tall. If there are 2.54 centimeters in an
inch, who is taller?
? Do you have a conversion factor?
YES!!!
1 inch = 2.54 cm
60 inches X
2.54 cm
1 inch
= 152.4 cm
Sara is taller
2. Michael tells Sara he weighs 104 pounds. Sara says
she is 44 kilograms. If there are 2.2 pounds in a kilogram,
who is heavier?
? Do you have a conversion factor?
YES!!!
1 kg = 2.2 pounds
44 kg X
2.2 pounds
1 kg
= 96.8 pounds
Rounds to 97 pounds
Michael is heavier