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

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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

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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