Lab 5 March 3

Scientific Method and Inquiry

  • The scientific method is a systematic approach to exploring questions and conducting experiments to develop insights and obtain answers.

Overview of the Scientific Method Steps

  1. Question

    • The first step involves identifying a question you wish to explore.
    • Example: "Does water temperature affect how fish swim?"

  2. Hypothesis

    • A hypothesis is a statement predicting an outcome based on observations, which must be tested through experimentation.
    • Example: "Water temperature affects how fast goldfish will swim."

  3. Prediction

    • This step involves predicting the expected results of the experiment.
    • Example: "If I warm up the water, then the fish will swim faster."

  4. Experiment

    • Conduct the experiment to test the hypothesis.
    • Example setup: one fish tank with cold water and another with warm water, observing the swimming speed of the fish.

  5. Conclusion

    • Analyze the results of the experiment to conclude whether to reject or fail to reject the hypothesis.
    • Failure to reject: if fish swim faster in warm water.
    • Reject: if there is no difference in swimming speed.

Important Notes on Hypothesis Testing

  • It's crucial to note that we do not use the terms "prove" or "accept" in scientific experimentation because it leaves room for uncertainty regarding the results.
  • Example comparison: In criminal law, a person is either found guilty or not guilty based on evidence, but one does not declare them innocent unless there is absolute proof.

Difference Between Hypothesis and Theory

  • A hypothesis is a preliminary statement with no experimental backing yet.
  • A theory is well-supported by extensive scientific and mathematical evidence and has undergone extensive testing and scrutiny.
    • Example: The Big Bang Theory is accepted due to substantial evidence, despite being unprovable due to its historical context (13.8 billion years ago).
  • Emphasis: On tests or assignments, use the term hypothesis instead of theory.

Variables in Experiments

  • Independent Variable

    • The factor manipulated by the experimenter.
    • In the fish example, the independent variable is water temperature.

  • Dependent Variable

    • The factor being measured in the experiment.
    • Example: The swimming speed of the fish.

  • Control Variables

    • Variables that are kept constant to ensure a fair test.
    • Example: Same amount of water, same source of water, similar lighting conditions, same ambient temperature.
Control Group vs. Experimental Group
  • A control group (negative control) does not receive the independent variable.
  • An experimental group (positive control) receives the independent variable.
  • Example: In testing a new drug, one group receives the medication and another an inert placebo.
  • Ensure control variables and groups are as similar as possible to isolate the effects of the independent variable.

Important Considerations for Hypotheses

  • A hypothesis must be testable through experimental means.
  • Example of a non-testable hypothesis: "Why is the sky blue?" This question cannot be answered with a simple experiment.

Summary of Key Concepts

  • Hypothesis: Testable statement predicting the outcome of an experiment.
  • Theory: Well-supported framework developed through rigorous testing.
  • Control Variables: Ensured consistency across experiments to eliminate external factors.
  • Independent and Dependent Variables: Clearly defined to isolate the effect being studied.