SCIENTIFIC UNITS OF THE MEASURING SYSTEM
SCIENTIFIC UNITS OF THE MEASURING SYSTEM
Measurements
Components of a Measurement•Numerical quantity•Unit•Name of substance
Numericalquantity
325.0 mL water
Name of the substanceunit
Metric System
• Also called the International or SI system.
• Based on # 10.
• SI states base Units.
• Other units derived from base units.
• Prefixes indicate power of ten.
SI BASE UNITS
Magnitude Name Symbol• Length meter m• Mass kilogram kg• Time second s• Temperature Kelvin K• Amount mole mol• Current ampere A• Luminous candela cd
Common Metric Prefixes
Prefix Symbol Decimal Exponential
Mega M 1 000 000 106
kilo k 1000 103
centi c 0.01 10-2
milli m 0.001 10-3
micro µ 0.000 001 10-6
Derived Units
Volume = side x side x side
Volume = m3 or Liter
Density = mass/volume
Density = kg/m3
MASS is the amount of matter in an object.
MASS = WEIGHT?
90 kg 90 kg
Earth Moonw = 882 N w= 147 N
w = m gWeight is force
Prentice-Hall ©2002 Burns 4/e Chapter 3 Slide 8 of 59
Mass Units
• Important Equivalences for mass messures:
• 1 kg = 1000g 1 g = 0.001 kg
• 1 mg = 0.001 g 1 g = 1000 mg
• 1 μg = 0.001 mg = 0.000001 g
• 1 g = 1,000,000 µg
Prentice-Hall ©2002 Burns 4/e Chapter 3 Slide 9 of 59
Insert figure 3.10
Equivalent Mass
Prentice-Hall ©2002 Burns 4/e Chapter 3 Slide 10 of 59
Volume Equivalneces
• 1 m3 = (100 cm)3 = (100)3 cm3 =
• 1,000,000 cm3
• 1 cm3 = 1 cc = 1 mL (milliliter)
• 1mL = 0.001 L y 1000mL = 1 L (liter)
• 1 L = 1 dm3 = 0.001 m3
• 1mL = 1000 µL (microliter, a million de liters)
Prentice-Hall ©2002 Burns 4/e Chapter 3 Slide 11 of 59
Insert figure 3.5
Relation between measures of volume and length
Prentice-Hall ©2002 Burns 4/e Chapter 3 Slide 12 of 59
Insert figure 3.13
Measure a volume lecture
Observe the
concave edge
Derived UnitsUsing the information found in the web
page: http://www1.bipm.org/en/si/
Answer the following questions:a)Why is it name SI?
b)when the world’s adopt the SI?c)What is the Importance of SI?
d)Make a table of base units definition.e) Make a table of derived units.
ACT #4
SCIENTIFIC UNITS OF THE MEASURING SYSTEM
Prentice-Hall ©2002 Burns 4/e Chapter 3 Slide 16 of 59
Insert Fig. 3.4
Length Units
UNIT SYSTEMS’ :
* SI: Metric System (m/k/s)
* USCS: U.S. Customary System Unit (f/p/s)
Measurements
Measurements
What does TO MEASURE mean?
To compare a magnitude with other of the same kind.
* Measurements are expressed in unit values
Measurements
a)15 ft to m
b)35 m to ft
c)300 m/s to km/h
d)80 ft/s to km/h
e)5 m2 to cm2
Convert: 1 m = 3.28 ft1 kg = 2.20 lb1 in.= 2.54 cm1 mi.= 1 609 m1 gal. = 3.785 L1 yd = 3 ft1 L = 1 000 cm3
1 dm = 10 cm1 oz. =30.56 mL
Now…
Join in pairs and
answer the class
activity.
Convert: 1 m = 3.28 ft1 kg = 2.20 lb1 in.= 2.54 cm1 mi.= 1 609 m1 gal. = 3.785 L1 yd = 3 ft1 L = 1 000 cm3
1 dm = 10 cm1 oz. =30.56 mL
# . # # x 10(+ / - power)
SCIENTIFIC NOTATION
a) 1 080 000 m
b) 0.000 005 s
c) 53 760 000 g
d) 0.000 047 42 s
e) 0.008 524 9 m
Use Scientific Notation and prefixes to express the following magnitudes:
ACT #2
Bibliography
• Fundaments of Chemistry
Ralph A. Burns
Prentice Hall