Chapter 2Section 1

Standards of Measurements

•Standard–Exact quantity that people agree to use

•SI System–International System of Units & Measurements–AKA Metric System

• Improved version of the metric system• Base 10 number system• Universally accepted & understood by scientists

throughout the world

Types of Units

• Base Units–Units from which ALL other

units are made (derived)

• Derived units–Combinations of base units

SI Base Units

Quantity MeasuredQuantity Measured UnitUnit SymbolSymbolLength Meter m

Mass Kilogram kg

Time Second s

Temperature Kelvin K

Amount of Substance Mole mol

Electric Current Ampere A

Intensity of Light Candela cd

BIG Common Prefixes

PrefixPrefix SymbolSymbol Multiplying FactorMultiplying Factor

Tera- T 1,000,000,000,000Giga- G 1,000,000,000Mega- M 1,000,000Kilo- k 1,000

Hecto- h 100Deka dk 10

Small Common PrefixesPrefixPrefix SymbolSymbol Multiplying FactorMultiplying Factor

Deci- d 0.1Centi- c 0.01Milli- m 0.001

Micro- μ 0.000 001Nano- n 0.000 000 001Pico- p 0.000 000 000 001

Femto- f 0.000 000 000 000 001

Scientific NotationM x 10n

• Way of expressing very BIG or very SMALL numbers

• Expresses numbers as powers of ten

• Numerical (M) is between 1.0 and 10

• Contains exact number of sig. figs.

• Pos. exponent (n) is a BIG number

• Neg. exponent (n) is SMALL number

Converting Units• Factor Label Method

– State Given Factor Unit

– Add Railroad Tracks

– Show = _______ name desired units

– Insert equivalents until desired unit is achieved

– Multiply to find resulting value

1 in = __?__ ft

1 in x _________ = _________ft

12 in = 1 ft

1 in x _________ = _________ft1 ft12 in

.083

Chapter 2Section 2

Precision vs. Accuracy

• Precision– Describes the degree of exactness of a

measure

• Accuracy– Describes how well the results of an

experiment agree with the standard value

• Parallax–The apparent shift in the position of an object when it is viewed from different angles.

Sig Figs• Nonzero digits are always significant• Zeros between 2 other sig figs are

always significant (sandwich rule)• After a decimal point, the LAST or

FINAL digit is significant (little piggy)

• Zeros that are placeholders are NOT significant

• When adding with sig figs– In the FINAL answer…Use same number

of decimal places as the least precise item being added

• When multiplying with sig figs– In the FINAL answer…Use the same

number of sig figs as the least of the items being multiplied

Chapter 2Section 3

Visual Data

• Line Graph– Shows relationship between dependent

variable and independent variable

• Bar Graph– Comparing info collected by counting

• Pie Graph– Part to Whole

Classroom Temperature

0

2

4

6

8

10

12

14

16

18

20

22

24

26

0 5 10 15 20 25

Time (min)

Tem

p (

C) A

B

C

Bar GraphsClassroom Size (Jan 20, 2001)

0

1

2

3

4

5

6

Number of Students

Nu

mb

er o

f C

lass

roo

ms

Number ofClassrooms

20 21 22 23 24 25 26 27

Pie GraphHeating Fuel Usage

Electric10%

Coal10%

Other5%

Steam25%

Gas50%

Plotting Line Graphs

• See steps to follow on pg 31

Linear Relationships

y = mx + b

Y-intercept = b

Slope = m = rise = Δy

run Δx

Δ (delta) means change

Non-linear Relationships

Quadratic Relationships (parabola)

y = ax2 + bx + c

Inverse Relationship (hyperbola)

xy = a

y = a x