Scientific Method, Experiments, and Theories Study Guide

Scientific Method: A process done over and over that involves reporting results and reviewing. It is a planned way to answer a scientific question using observations.
Observation: Information gathered using your senses.
Hypothesis: An explanation that can be tested.
Prediction: Guesses made that scientists think will happen.
Evidence: Information or data used to support or reject an explanation.

Steps of a Scientific Investigation:
- Step 1: Ask a question.
- Step 2: Form a hypothesis.
- Step 3: Make a prediction.
- Step 4: Test it.
- Step 5: Collect and analyze evidence.
- Step 6: Draw conclusions.
- Step 7: Communicate results.
Characteristics of a Useful Hypothesis:
- Must be testable.
- Must be able to be supported or rejected by evidence.
Example of an Experimental Scientific Question:
- Does the amount of sunlight affect how fast a plant grows?
Proving a Hypothesis True:
- A hypothesis cannot be proven true.
- Reason: Evidence can support a hypothesis, but new evidence could show that it is wrong.
Purpose of Communicating Results:
- Scientists communicate their results so they can review, repeat, and learn from their investigation.

Experiment: A controlled test used to answer a scientific question.
Independent Variable: The variable that the scientist changes.
Dependent Variable: The variable that is measured or observed.
Comparison of Variables:
- The independent variable gets changed, while the dependent variable is measured.

Experimental Scenario:
- A scientist grew bacteria on gel in her lab to find out if the bacteria would grow faster on gel A or gel B.
- She placed a few bacteria on gel A and a few on gel B.
- After $24\,\text{hours}$ , she observed how many bacteria were present on each type of gel.
Identified Variables:
- Independent Variable: Type of gel, gel A and gel B.
- Dependent Variable: Amount of bacteria present after $24\,\text{hours}$ .

Theory: A well-supported explanation based on lots of scientific evidence.
Law: A statement that describes a pattern that consistently happens in nature.
Scientific vs. Everyday Usage of "Theory":
- Everyday Language: A theory can mean a guess.
- Scientific Context: A theory is an explanation supported by lots of evidence.
Transition from Hypothesis to Theory:
- If a hypothesis is repeatedly tested and supported by a large amount of evidence, it can contribute to the development of a theory.
Evidence Supporting Cell Theory:
- Scientists have repeatedly observed that all living things are made of cells.
- Scientists have repeatedly observed that new cells come from existing cells.

Test Scope: A comprehensive test covers every single item and concept on this study guide.
High-Priority Key Areas:
- Independent and Dependent Variables: Particular emphasis must be placed on understanding, comparing, and identifying independent and dependent variables in experimental setups.
- Vocabulary: Complete, thorough, and precise knowledge of all defined terms is essential.