Scientific Method and Hypothesis Testing

Scientific Method

• Science aims to understand nature and predict events.
• The process involves asking questions, collecting data (observations/measurements), and developing explanations (hypotheses).
• A valid hypothesis must explain data, make predictions, and be reproducible.
• A hypothesis becomes a theory when rigorously tested and consistently supported.
• A scientific law describes a repeatedly observed natural phenomenon (e.g., the law of thermodynamics).
• Scientific laws describe what happens, while theories explain why.
• Critical thinking (scientific thinking) can be applied to daily life.

Hypothesis Formation and Testing

• Scientific studies often start with an observation leading to a question.
• A possible explanation (hypothesis) is formed.
• Hypotheses are tested through experimentation.
• A controlled experiment isolates a single variable for testing.
• This involves an experimental group and a control group.
• Other variables may impact the results in real-world scenarios (e.g., environmental science).
• Mathematical modeling is used in scenarios with multiple interacting variables.

Inductive and Deductive Reasoning

• Inductive reasoning: Moves from specific observations to general conclusions.
  • Example: Observing multiple dogs barking at cars = conclusion: all dogs bark at cars (not necessarily true).
• Deductive reasoning: Moves from general principles to specific conclusions.
  • Used to reach logical conclusions based on scientific generalizations.
  • Example: All birds can fly, penguins are birds; therefore, penguins can fly (incorrect, and thus shows deduction can be invalid).

Example: Pesticide and Ants

• An entomologist observed fewer ants in an area with pesticide application.
• A controlled lab experiment was set up: one group of ants with pesticide exposure, one without.
• The ants avoiding the pesticide in the lab led to the conclusion that the pesticide repels them.
• This experiment does not account for wild differences, which may be significant, and the lab result does not necessarily apply to the field.