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MEASUREMENTAT THE CONCLUSION OF OUR
TIME TOGETHER, YOU SHOULD BE ABLE TO:
1. Explain the difference between the two types of observations
2. Give examples of 5 basic SI measuring units3. Give examples of 3 different derived units
from the basic SI units4. Vary the amounts of the SI measuring units
with 10 different prefixes and define each
SI MEASUREMENT
• Le Système International d ‘Unités
• Adopted in 1960 by the General Conference on Weights and Measures.
• International Standards are kept in France.
• Among countries with non-metric usage, the U.S. is the only country significantly holding out. The U.S. officially adopted SI in 1866.
• Liberia and Myanmar are changing over.
Information from U.S. Metric Association
Liberia
BASE SI UNITS
QuantityQuantity UnitUnit SymbolSymbol
LengthLength metermeter mm
MassMass kilogramkilogram kgkg
TemperatureTemperature kelvinkelvin KK
TimeTime secondsecond ss
Amount of Amount of SubstanceSubstance
molemole molmol
Luminous Luminous IntensityIntensity
candelacandela cdcd
Electric CurrentElectric Current ampereampere aa
TYPES OF OBSERVATIONS AND MEASUREMENTS – PAGE 25
• We make QUALITATIVE observations of reactions — changes in color and physical state.
• We also make QUANTITATIVE observations that involve MEASUREMENTS with numbers and units.
STATING A QUANTITATIVE MEASUREMENT
In every measurement there is a
Number (Quantity) followed by a
Unit from a measuring device
METRIC PREFIXES – PAGE 40
You Will Need to Know:
The Grand Master King Henry Died by Drinking Chocolate Milk Monday Night
Prior
1 meter (m)
1 kilometer (km)
1 dm (decimeter)1 cm (centimeter)1 mm (millimeter)
1 m (micrometer)
1 nm (nanometer)
103 meters = 1 km
10 dm = 1 m100 cm = 1 m103 mm = 1 m
106 m = 1 m
109 nm = 1 m
110
103
10-310-210-1
10-6
10-9
A Weighty ProblemA Weighty Problem
On 9/23/99, $125,000,000 Mars Climate Orbiter entered Mars’ atmosphere 100 km lower than planned and was destroyed by heat.
1 lb = 1 N
1 lb = 4.45 N
“This is going to be the cautionary tale that will be embedded into introduction to the metric system in elementary school, high school, and college science courses ‘till the end of time.”
Weight is force of the gravitational pull on an object. It would be different on the moon than it is on earth.
Mass is a measure of the amount of matter in an object.Mass is a measure of the amount of matter in an object.
Mass and weight are directly related as long as we remain on earth at the same elevation. That is, if one object has twice the mass of another, then its weight
on earth would also be twice as large.
However, if we take the same object to Denver, Colorado, the mass stays the same but the weight would be
different. Why??
Mass and Weight
MASS VS. WEIGHT• Mass: Amount
of Matter • (grams,
measured with a BALANCE)
• Weight: Force exerted by the
mass, only present with
gravity • (pounds,
measured with a Scale)
Can you hear Can you hear me now?me now?
Length and Volume
1 m = 10 dm therefore 1 m3 = 103 dm3
1 dm = 10 cm therefore 1 dm3 = 103 cm3
1 L = 1 dm3 and 1 L = 103 mL
so
1 L = 1 dm3 = 103 mL = 103 cm3 = 103 cc
so
This means that 1 milliliter (mL) is the same as 1 cubic centimeter (cc). These terms are often
used interchangeably.
UNITS FOR VOLUME UNITS FOR VOLUME
mm33
cmcm3 3
dmdm33
L L Liter
mLmL
1 dm1 dm33 = = 1 L
1 cm1 cm3 3 = = 1 mL
OTHER DERIVED SI UNITS
QuantityQuantity UnitUnit SymbolSymbol
VolumeVolume cubic metercubic meter mm33
DensityDensity kilograms per kilograms per cubic metercubic meter
kg/mkg/m33
SpeedSpeed meter per secondmeter per second m/sm/s
NewtonNewton kg m/ skg m/ s22 NN
EnergyEnergy Joule (kg mJoule (kg m22/s/s22)) JJ
PressurePressure Pascal (kg/msPascal (kg/ms22)) PaPa
UNITS FOR ENERGY
• Joule JJoule J
• calorie 1 cal = 4.184 J 1 cal = 4.184 J
1 cal = quantity of heat needed to raise the 1 cal = quantity of heat needed to raise the temperature of 1 g of water by 1 temperature of 1 g of water by 1 ooC.C.
1 kcal = 1 kcal = 10001000 cal cal
MEASUREMENTLET’S SEE IF YOU CAN:
1. Explain the difference between the two types of observations
2. Give examples of 5 basic SI measuring units3. Give examples of 3 different derived units
from the basic SI units4. Vary the amounts of the SI measuring units
with 10 different prefixes and define each5. Explain the difference between mass and
weight6. List and explain 5 different units for volume.
LEARNING CHECK
Match L) length M) mass V) volume
____ A. A bag of tomatoes is 4.6 kg.
____ B. A person is 2.0 m tall.
____ C. A medication contains 0.50 g Aspirin.
____ D. A bottle contains 1.5 L of water.
M
L
M
V
LEARNING CHECK
What are some U.S. units that are used to measure each of the following?
A. length
B. volume
C. weight
D. temperature
LEARNING CHECK
1. 1000 m = 1 ___ a) mm b) km c) dm
2. 0.001 g = 1 ___ a) mg b) kg c) dg
3. 0.1 L = 1 ___ a) mL b) cL c) dL
4. 0.01 m = 1 ___ a) mm b) cm c) dm