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Chapter 1
Science Skills
Science and Technology
• “Science” derives from Latin
scientia, meaning “knowledge”
• Science: a system of knowledge
and the methods used to find that
knowledge.
• Technology: the use of knowledge
to solve practical problems.
• Difference: Science expands
knowledge; technology applies
knowledge.
Physical Science
• Science: divided into social and
natural
• Natural science: 3 branches—
physical, Earth and space, life
• Physical science: a branch of
natural science that focuses on nonliving things
• 2 main areas: chemistry and
physics
Chemistry and Physics
• Chemistry: the study of the
composition, structure, properties,
and reactions of matter
• Physics: the study of matter and
energy and the interactions between
the two through forces and motion
Earth Sciences
• Geology: the study of the origin,
history, and structure of earth.
• Astronomy: the study of the
universe beyond Earth, including the
sun, moon, planets, and stars
Life Sciences
• Biology: the study of living things
• Bios: Greek for “life”
• -ology: “study of”
Scientific Method
• Definition: an organized plan for
gathering, organizing, and
communicating information.
• Goal: to solve a problem or to better
understand an observed event
Steps in the Scientific
Method
(1) Make observations
(2) Form a hypothesis
(3) Test the hypothesis
(4) Draw conclusions
(5) Develop a theory
Definitions
• Observation: information obtained
through the senses
• Hypothesis: a proposed answer to a
question
• Scientific theory: a well-tested
explanation for a set of observations or
experimental results
• Note: Theories are never proved
• Scientific law: a statement that
summarizes a pattern found in nature
Models
• Model: a representation of an object
or event
• Models make it easier to understand
things that might be too difficult to
observe directly
Scientific Notation
• Scientific notation: a way of
expressing a value as the product of
a number between 1 and 10 and a
power of 10.
Example 1
• Example: speed of light
• Numeric value: 300,000,000 m/s
• In scientific notation: 3.0 x 108 m/s
Example 2
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•
•
•
Example: speed of a snail
Numeric value: .00086 m/s
In scientific notation: 8.6 x 10-4 m/s
Note: If the number you begin with is
less than 1, your exponent will be
negative.
Multiplying in Scientific
Notation
• Rule: Multiply the numbers that
appear before the multiplication
signs and ADD the exponents.
• (3.0 x 108m/s) x (5.0 x 102s)
• Step 1: Multiply: 3 x 5 = 15
• Step 2: Add exponents: 108 + 102 =
1010
• “Raw” answer: 15 x 1010 m
• Final answer: 1.5 x 1011m
Dividing in Scientific
Notation
• Rule: Divide the numbers that appear
before the exponential terms and
SUBTRACT the exponents.
• 1.5 x 1011m
3.0 x 108 m/s
• Step 1: Divide numbers 1.5/3 = 0.5
• Step 2: Subtract exponents11-8 = 3
• Raw answer: 0.5 x 103s
• Final answer: 5.0 x 102s
Practice Problem # 1
• (7.6 x 10-4 m) x (1.5 x 107 m) = ?
• Step 1: Multiply the numbers that
appear before the multiplication
signs.
• 7.6 x 1.5 = 11.4
• Step 2: Add the exponents.
• 10-4 + 107 = 103
• Raw answer: 11.4 x 103 m2
• Final answer: 1.14 x 104 m2
Practice Problem # 2
•
•
•
•
•
•
•
•
0.00053 / 29
Step 1: Convert to scientific notation
5.3 x 10-4 / 2.9 x 101
Step 2: Divide the numbers that appear
before the exponential terms
5.3 / 2.9 = 1.8
Step 3: Subtract the exponents
10-4 – 101 = 10-5
Answer: 1.8 x 10-5
Bell-ringer
• What is a Kelvin?
Units of Measurement
• For a measurement to make sense,
it requires both a number and a
unit.
• Scientists do not measure in inches,
feet, and degrees Fahrenheit.
• Scientists use a set of measuring
units called SI
SI Definitions
• Length: the straight-line distance
between two points
• Mass: the quantity of matter in an
object or sample
• Volume: the amount of space taken
up by an object
• Density: the ratio of an object’s
mass to its volume (D = m/v)
SI Base Units
•
•
•
•
•
Length  meter (m)
Mass  kilogram (kg)
Temperature  Kelvin (K)
Time  second (s)
Amount of substance  mole
Significant Figures
• Significant figures: all the digits
that are known in a measurement,
plus the last digit that is estimated.
• The fewer the significant figures, the
less precise the measurement is.
• The precision of calculated answer
is limited by the least precise
measurement used in the
calculation.
Significant Figure Problem
• A piece of iron weighs 34.73 grams. Its
volume is 4.42 cubic centimeters.
• (a) What is its density?
• Answer: D = m/v = 34.73/4.42
• (b) How many significant figures should
the answer contain?
• Answer: 3
• Why: Because the least precise
measurement (volume) has 3 significant
figures.
• Final answer: 7.86 g/cm3
Measuring Temperature
• Thermometer: an instrument that
measures temperature.
• Fahrenheit: water freezes at 32o
and boils at 212o.
• Celsius: water freezes at 0o and
boils at 100o.
• Note: A degree Celsius is almost
twice as large as a degree
Fahrenheit.
Converting between C and
F
• Celsius: (oF- 32) x .55
• Fahrenheit: (oC x 1.8) + 32o
Practice Problem 1
• Question: 32oC is equivalent to
what Fahrenheit temperature?
• Answer: 89.6oF
Practice Problem 2
• Question: 95oF is equivalent to what
Celsius temperature?
• Answer: 34.7oC
Kelvin
• The SI base unit of temperature is
the kelvin (K).
• A temperature of 0 K [absolute zero]
refers to the lowest possible
temperature that can be reached
(over 500 below 0 in oF).
• In oC, this temperature is -273.15.
Converting between C and
K
• K = oC + 273
• See Figure 19 on p. 20.