ISB 202

The Natural World and the Process of Science

  • Day-to-Day Experiences and Scientific Testing

    • The importance of evidence in understanding the natural world.

    • Comparing consumer experiences (buying products) with scientific practices.

    • Evidence is foundational in scientific inquiry.

  • Definition of Evidence

    • Evidence is data or material that supports claims or hypotheses in the scientific process.

  • The Process of Science

    • A circular process that encompasses several steps:

    • Observation of a Problem

      • An example stated: "I don't have a bottle that holds my water cold or hot."

    • Research

      • Investigating existing solutions or relevant technologies available in the market.

    • Formation of a Hypothesis

      • Definition: An educated guess; a potential explanation that is testable.
        Example hypotheses could involve the effectiveness of a water bottle in maintaining temperature.

    • Testing

      • Conducting experiments to gather data points.

    • Sharing Results

      • Presenting findings to peers, which can encourage further exploration and discussion.

  • Importance of Knowledge and History in Science

    • Shared by a participant, Tiara.

    • Historical context helps in decision-making for the present and future.

    • "Knowledge for the future" highlights the significance of understanding history in scientific contexts.

  • Historical Case: Claire Patterson and Lead Dating

    • Introduction to Claire Patterson

    • Known for accurately determining the age of Earth.

    • Used a method called lead dating to analyze the transformation of uranium to lead in rocks post-supernova events.

    • The Discovery of Excess Lead

    • Patterson discovered additional types of lead in surface rock samples, leading to further research on atmospheric leads.

    • Lead is a heavy metal that mimics calcium and can accumulate in biological systems, causing developmental issues.

    • The concern: lead levels were over a thousand times higher than expected, largely due to human activities.

  • Lead Contamination and Gasoline

    • Introduced in the 1920s when lead was added to gasoline to improve performance (reduce engine knocking).

    • Example of a tragic incident involving Henry Leland, the founder of Cadillac, who developed model 30 after a friend's death due to a mechanical failure.

  • Health Risks and Advocacy

    • Over-reliance on leaded gasoline led to public health threats, especially affecting workers and local populations.

    • Claire Patterson faced significant resistance from powerful corporate interests concerned with profits over public health (Ethyl Corporation, General Motors, etc.).

    • Kegel Rule: The burden of proof fell on the victims (public) to demonstrate harm, echoing concerns with other industries (e.g., tobacco, asbestos).

  • Importance of Scientific Literacy

    • Essential for critically evaluating information and claims.

    • Encourages questioning of sources and validity of scientific claims, especially when commercial interests are involved.

  • Hypothesis Definition and Example

    • A hypothesis is a potential and testable explanation for a set of observations.

    • Patterson's hypothesis regarding atmospheric deposition of leads based on surface sample observations.

    • Education around what constitutes a valid hypothesis versus unsupported claims.

  • Variables in Scientific Testing

    • Three types of variables:

    • Independent Variable: The factor changed in the experiment (e.g., the type or concentration of a substance).

    • Dependent Variable: What is measured in the experiment (e.g., outcomes of reactions or physical changes).

    • Control Variables: Factors that remain constant to ensure only the independent variable is affecting the dependent variable.

  • Real-World Application Case Study: Coral Reefs and Nitrogen Levels

    • Observational study where temperature alone is not the sole factor for coral bleaching; nitrogen pollution from human activity plays a critical role.

    • The study manipulated nitrogen concentrations, testing their effects on coral health while controlling temperature.

    • Each type of variable (independent, dependent, control) is illustrated in the context of coral bleaching research.

  • Evaluating Scientific Claims:

    • Claim, Evidence, Reasoning (CER) Model

    • Claim: A statement or assertion about a phenomenon.

    • Evidence: Data or support for the claim, e.g., effects of fossil fuel emissions.

    • Reasoning: The rationale connecting evidence to the claim.

    • Example application of the CER method involves analyzing marketing claims creatively versus scientifically valid claims.

  • In-Class Activity

    • Students will engage in a group activity using a CER table format to assess different claims based on provided data or scenarios.

    • Aim: To practice critical thinking and solidify understanding of scientific processes in a hands-on manner.