Post on 02-Jan-2016
Units of MeasurementScience 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 MeasurementDistanc
eMass Time Area/
VolumeTemperature
inch milligram
hours in^2, in^3
Fahrenheit
meter ounces seconds m^2, m^3
Celsius
mile pounds days Liters Kelvin
feet gram months Galloncentimeter
kilogram
years Quart
millimeter tons minutes Pint
How to use a ruler:1. Determine if you are
measuring in centimeters or inches and find that unit’s side of the ruler.
inches
centimeters
How to use a ruler2. Place the “0” mark at one end of the
object you are measuring.
“0” mark
How to Use a Ruler3. Record the ruler marking that falls at
the other end of the objectFor INCHES: - Each dash after a whole inch is 1/16
of an inchFor CENTIMETERS: - Each dash after a whole centimeter is
1/10 of a centimeter
Measurement Lab
Relative SizeUnit Relative
SizeExamples
Inches 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
Paper, small machine parts, body parts
Millimeters 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 (ml)– kilogram (kg)
Metric PrefixesPrefix
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 m = 1000 mm
• 1 km = 1000 m
• 1 ft. = 12 in.
• 1 yd. = 3 ft.
• 1 min = 60 s
• 1 hr = 60 min
• 1 day = 24 hr.
• 1 year = 365 days
Conversion Hints• Staircase Method
Rules to using the Staircase Method of
conversion1. Find the unit on the staircase where
you are STARTING. ex. Convert 5 m = ________ cmYou are starting at m.
2. Count up or down the stairs ending on the unit you need to convert to. ex. 5 m = ________ cmYou need to convert to cm.
3. If you counted UP the stairs, move the decimal point LEFT.4. If you counted DOWN the stairs, move the decimal point RIGHT.
ex. 5 m = ________ cm
5 m = ______ cm
Move decimal 2 places to the right.
5 m = 500 cm
PRACTICE!!
• You will get a sheet to practice conversions.
• Use the staircase method (it is the easiest!)
• Do not be afraid to ask for help.