Chapter 1: Nature of Science and Scientific Theories

🌟 What Science Is

Science is a systematic process used to understand the natural world through evidence, testing, and reasoning.

Key Features of Science

  • Based on empirical evidence (observations + data)

  • Uses testable and repeatable methods

  • Produces predictive explanations

  • Open to revision when new evidence appears

Science is NOT based on belief, opinion, or authority — it is based on evidence.

Scientific Method Diagram Scientific Method Worksheet | Scientific

🌟 What Science Is Not

The EOC requires you to differentiate:

Science

Uses evidence, experiments, and logical reasoning.

Nonscience

Topics that cannot be tested (e.g., art, philosophy).

Pseudoscience

Claims that pretend to be scientific but lack:

  • Controlled testing

  • Peer review

  • Reliable evidence

  • Repeatability

Examples: astrology, crystal healing.

Science vs Pseudoscience - Tabular Form | String theory, Molecular ...

🌟 Scientific Theories vs. Scientific Laws

The EOC LOVES this distinction.

Scientific Theory

A well‑supported explanation of natural phenomena.

  • Based on many lines of evidence

  • Explains why something happens

  • Can be revised with new evidence

Examples:

  • Cell Theory

  • Theory of Evolution

  • Germ Theory

Scientific Law

A statement describing a natural pattern.

  • Tells what happens

  • Usually mathematical

  • Rarely changes

Examples:

  • Law of Gravity

  • Law of Superposition

⭐ Important EOC Point:

Theories do NOT become laws.
They serve different purposes.

🌟 Reliability of Scientific Data

The EOC requires you to evaluate whether data is reliable.

Reliable Data Comes From:

  • Controlled experiments

  • Large sample sizes

  • Repeated trials

  • Peer‑reviewed sources

  • Clear, unbiased methods

Unreliable Data Includes:

  • Small sample sizes

  • No control group

  • Biased sources

  • Unrepeatable results

  • Unsupported claims

🌟 Experimental Design (EOC Essentials)

You must be able to interpret or critique an experiment.

Independent Variable

The factor the scientist changes.

Dependent Variable

The factor that is measured.

Constants

Variables kept the same.

Control Group

Used for comparison; does NOT receive the independent variable.

Experimental Group

Receives the independent variable.

Variables Unit - Mrs. Nesley's Classroom Page

🌟 Causal Relationships

The EOC expects you to determine whether data shows:

Correlation

Two things happen together.

Causation

One thing directly causes another.

Science requires evidence of causation, not just correlation.

🌟 Development of Scientific Theories

The EOC requires you to analyze how theories develop.

Theories grow stronger when:

  • New evidence supports them

  • Predictions are confirmed

  • Multiple fields agree (biology + chemistry + geology)

  • They withstand peer review

Theories weaken when:

  • Evidence contradicts them

  • Predictions fail

  • Better explanations appear

Science is self‑correcting.

🌟 Peer Review

Before research is accepted, other scientists must:

  • Review the methods

  • Check the data

  • Repeat the experiment

  • Confirm the results

Peer review prevents bias, fraud, and errors.

🌟 Models in Science

Models help scientists understand things that are too:

  • Small (atoms)

  • Large (solar system)

  • Complex (ecosystems)

Models are useful, but not perfect.