Overview
This lecture introduces foundational concepts in scientific thinking and the scientific method, distinguishing between hypotheses, theories, laws, facts, and beliefs.
The Scientific Method and Hypotheses
- Science is a process of gaining knowledge about the observable universe.
- A hypothesis is an educated guess that must be testable and falsifiable by evidence.
- Hypotheses should align with existing scientific knowledge.
- Null hypothesis: predicts no significant difference between expected and observed data.
- Alternative hypothesis: the main idea or prediction being tested by the researcher.
Types of Scientific Knowledge
- A fact is an observation that can be repeatedly confirmed, like water freezing at 32°F.
- A belief is a claim not supported by disprovable evidence.
- Pseudoscience consists of claims or practices mistakenly regarded as scientific (e.g., astrology).
Theories, Laws, and Proof in Science
- A scientific theory explains how or why certain phenomena occur, based on extensive evidence and peer review.
- Theories are falsifiable and can change with new evidence.
- A scientific law describes what happens, typically using mathematical relationships (e.g., F = ma).
- Theories explain "how and why"; laws describe "what."
- Theories do not become laws with more evidence—they are fundamentally different.
- Science cannot prove anything absolutely; it can only disprove or support ideas.
Analogies and Clarifications
- Scientific conclusions are like inferring a hidden shape from evidence; all evidence may support a conclusion, but absolute proof is not possible.
Key Terms & Definitions
- Science — the process of gaining knowledge about the natural world.
- Hypothesis — a testable, falsifiable prediction based on current knowledge.
- Null hypothesis — predicts no significant difference between groups or conditions.
- Alternative hypothesis — the main prediction researchers test.
- Fact — a repeatedly confirmed observation.
- Belief — a claim not supported by disprovable evidence.
- Pseudoscience — claims that appear scientific but lack disprovable evidence.
- Theory — an explanation for natural phenomena, based on evidence, that explains how or why.
- Law — a description of what happens, often expressed mathematically.
Action Items / Next Steps
- Review your notes on the scientific method, types of hypotheses, and differences between theories, laws, and facts.
- Prepare for upcoming units covering foundational math and statistics for AP Biology.