Question

8th grade science unit 1 exam review
topic 1. scientific method
define the following key terms
experiment:
scientific investigation:
observation:
inference:
hypothesis:
test variable:
outcome variable:
controlled variable:
control group:
data:
empirical evidence:
repetition:
replication:
valid:
analyze:
conclusion:
scientific investigations

1. what is the difference between a control variable and fixed variable? provide an example of each:

control variable fixed variable
definition: definition:
example: example:

Explanation:

• Experiment: A procedure carried out to test a hypothesis under controlled conditions.
• Scientific investigation: A systematic approach to answer scientific questions through observation, experimentation, etc.
• Observation: Gathering information using senses or instruments.
• Inference: A conclusion based on observations and prior knowledge.
• Hypothesis: A testable prediction about the relationship between variables.
• Test variable (Independent variable): The variable that is changed or manipulated in an experiment.
• Outcome variable (Dependent variable): The variable that is measured and changes in response to the test variable.
• Controlled variable: A variable that is kept the same throughout an experiment to ensure only the test variable affects the outcome.
• Control group: The group in an experiment that does not receive the treatment or has the independent variable set to a standard value for comparison.
• Data: Facts, figures, and other evidence collected during an investigation.
• Empirical evidence: Evidence based on observation and experimentation.
• Repetition: Repeating an experiment multiple times by the same researcher.
• Replication: Another researcher repeating an experiment to verify results.
• Valid: An experiment is valid if it measures what it is supposed to measure.
• Analyze: To examine data to draw conclusions.
• Conclusion: A statement that sums up the results of an experiment and whether the hypothesis was supported.
• For the difference between control and fixed variables: A control variable is deliberately held constant to isolate the effect of the independent variable. A fixed variable is a characteristic that cannot be changed during the experiment. For example, in an experiment testing plant growth with different fertilizers, the amount of sunlight a plant receives can be a control variable (kept the same for all plants). The type of plant species used is a fixed variable (once chosen, it cannot be changed during the experiment).

Answer:

• Experiment: A procedure to test a hypothesis under controlled conditions.
• Scientific investigation: Systematic approach to answer scientific questions.
• Observation: Gathering information with senses or instruments.
• Inference: Conclusion based on observations and knowledge.
• Hypothesis: Testable prediction about variable - relationships.
• Test variable: Variable that is manipulated.
• Outcome variable: Variable that is measured and responds to the test variable.
• Controlled variable: Variable kept the same in an experiment.
• Control group: Group without treatment for comparison.
• Data: Collected evidence during investigation.
• Empirical evidence: Evidence from observation and experiment.
• Repetition: Repeating an experiment by the same researcher.
• Replication: Another researcher repeating an experiment.
• Valid: Experiment measures what it intends to.
• Analyze: Examine data to draw conclusions.
• Conclusion: Summarizes results and hypothesis - support status.
• Control Variable Definition: Deliberately held constant to isolate independent - variable effect. Example: Amount of sunlight for plants in a fertilizer experiment.
• Fixed Variable Definition: A characteristic that cannot be changed during the experiment. Example: Type of plant species in a plant - growth experiment.