SCI 111: Introduction to Physics and Chemistry

Chapter 1What Is Science?

How would you describe this baseball to someone over the phone?

Properties.

Quantifying Properties (aka Measurements)

Measurement is a Process(3 steps)

1. “Comparing”

2. “Procedure”

3. “Counting”

Measurement always contains: • Number (How Much?)• Name (Of What?).

Nature of Science

• Collecting observations• Developing explanations• Testing explanations

Scientific Method / Scientific Investigation

3 General Scientific Activities

“Understanding thru experimental evidence”.

Nature of Science

• “Tentative” explanation about a phenomenon Thought-derived or experiment-derived An “Educated Guess” compatible with the data Provides framework for understanding or describing it

• Tested by Experiments / Controlled Experiments Support: “Re-creation” of an event or occurrence ; “Reproducible”

• Could lead to a Theory or Scientific Law

Hypothesis

Nature of Science

• Broad working hypothesis

• Based on extensive experimental evidence

• Tells you “Why” something happens.

Theory

Fig 1.16

Alfred Wegener(1880-1930)

Nature of Science

• Wider-ranging phenomena• Can be expressed as:

Scientific Law Scientific Principle• Helps explain a more narrow range • More specific set of relationships.

• Both help explain relationships that occur in nature consistently time after time• Describe how objects behave or act

Fig 1.14

Nature of Science

• Description of a theory or idea that accounts for all known properties

• Helps us understand something that cannot always be directly observed

• Examples: Physical Mental (Conceptual) An Equation.

Model

Fig 1.15

Equations and Symbols

Equations • Mathematical relationships between properties• Used to:

Describe a property Define a concept Describe how quantities change relative to each other

Symbols• Represent specific quantities or measured properties• Shorthand for a message (e.g. Δ - a change in).

Understandings of Measurements

Measurement Systems

3 Fundamental Properties (Standard Units)(most basic “Of What?” terms)

Metric Systems (SI)

centimeter [cm]

gram [g]

LENGTH

MASS

TIME

meter [m]

mks cgs

kilogram [kg]

second [s] second [s]

p 5

Measurement SystemsOther properties are “derived” from the

Fundamental Properties

Fig 1.6

Fig 1.8

The extentThe extentof a surfaceof a surface

How much space How much space something occupiessomething occupies

Mass Density (ρ)• “Compactness of matter” • Ratio of mass to volume• Characteristic of a given

material

Table 1.4

• Represent larger or smaller amounts by factor of 10

• A “Simplification”• A movie giving a perspective

on powers of ten.

Fig 1.7

Metric Prefixes

Metric PrefixesTable 1.3 and in the front of textbook

Important ones toremember / know:

mega-kilo-

centi-milli-micro-

Understandings from Measurements• Mathematical Review (Appendix A)

Solving Equations Conversion of Units Scientific Notation

• How to Solve Problems Steps to success ; Not steps to memorize As you work problems, refer to this methodology.

Next Time

Begin Chapter 2: Motion