Transcript Units of Measurement - Two Rivers High School

Units of Measurement
Science 9
September 2014
Vocab
• Unit – a standard of measurement in which other
measurements are expressed.
• English System (United States Customary System) – system of
measurement used in the US, includes inches, gallons, pounds,
miles, etc.
• Metric System – system of measurement used in countries
other than the US and by the scientific community; units are
organized by factors of 10.
• Prefix – element placed at the beginning of a word that
changes the meaning of the word; in the metric system, it
indicates a unit smaller of larger than the basic unit by factors
of 10.
Why is measurement
important?
• Use it in daily life
–
–
–
–
Cooking
Construction
Decorating a room
Driving
• Communication
– Need to be able to communicate measurements
and distances to other people
Measurement & Physics
• Physicists try to find relationships between the
quantities they measure  use units of
measurement to do this
• Measure the very largest and smallest things in
the universe
– Smallest: mass of an electron = 0.000000911 yg
– Largest: light years (distances between stars and
galaxies
Units of Measurement
Distance Mass
Time
inch
milligram hours
meter
ounces
mile
feet
pounds
gram
centimeter kilogram
millimeter tons
seconds
days
months
years
minutes
Area/Vol
ume
in^2,
in^3
m^2,
m^3
Liters
Gallon
Quart
Pint
Tempera
ture
Fahrenheit
Celsius
Kelvin
How to use a ruler:
1. Determine if you are
measuring in centimeters
or inches and find that
unit’s side of the ruler.
centimeters
inches
How to use a ruler
2. Place the “0” mark at one end of the
object you are measuring.
“0” mark
How to Use a Ruler
3. Record the ruler marking that falls at
the other end of the object
For INCHES:
- Each dash after a whole inch is 1/16 of
an inch
For CENTIMETERS:
- Each dash after a whole centimeter is
1/10 of a centimeter
Measurement Lab
Relative Size
Unit
Inches
Relative Size Examples
1 in
Photo size, body parts
Feet
1 ft = 12 in
Height of people, room
size
Yard
1 yd= 3 ft
Football field
Meters
1 m ~ 1 yd
Height of people, track
length
Kilometers
1km = 1000m
Car travels, between cities
Centimeters
1 cm = 0.01 m
Millimeters
Paper, small machine
parts, body parts
1 mm = 0.001 m Coins
Two Main Systems of
Measurement
• United States Customary System (USCS)
• System International (SI)- Metric System
USCS
• Used in the U.S. and Burma
• Distance: inch (in), foot (ft), yard (yd),
mile (mi)
• Mass: pound (lb)
• Time: second (sec)
• Temperature: degrees Fahrenheit (F)
Metric System
• Used by all other countries and the scientific
community
• Units that are larger or smaller units than the basic
units are defined in multiples of 10
• Basic Units
–
–
–
–
–
Distance: meter (m)
Mass: gram (g)
Time: second (s)
Temperature: degrees Celsius
Volume: Litre (L)
Metric System: Prefixes
• Adding a prefix to a basic metric unit increases or
decreases the unit size by a factor of 10
• Prefixes are always added to the beginning of
Metric basic units
• For example,
– centimeter (cm)
– milliliter (mm)
– kilogram (kg)
Metric Prefixes
Prefix Symbol Relation to Basic
Unit
milli-
m
1000 mm = 1 m
centi-
c
100 cm = 1 m
deci-
d
10 dm = 1 m
deka-
da
1 dam = 10 m
hecto-
h
1 hm = 100m
kilo-
k
1 km = 1000 m
Common Unit Equivalencies
• 1 m = 100 cm
• 1 min = 60 s
• 1 m = 1000 mm
• 1 hr = 60 min
• 1 km = 1000 m
• 1 day = 24 hr.
• 1 ft. = 12 in.
• 1 yd. = 3 ft.
• 1 year = 365 days
Conversion Factors
• Each unit equivalency can be written as
TWO conversion factors.
• To make the conversion factors, place one
side of the unit equivalency on the top and
the other on the bottom of a fraction bar.
• Then, flip the fraction to get the second
conversion factor.