Scientific Method and Experimental Design

Scientific Method

• A set of steps to ensure scientific work is done correctly.
• Steps (processes) involved:
  • Ask a question.
  • Research the question.
  • Make a prediction (guess).
  • Experiment: collect evidence/measurements to answer the question.
  • Collect results (data).
  • Share results/start again (if results don't align with predictions, predict again and experiment differently).

Experimental Design

• Experiments use the scientific method to test ideas.
• Components of an experiment:
  • Clear question.
  • Hypothesis: statement about what will happen based on past observations.
  • Constants: factors kept the same to avoid affecting results.
  • Independent variable: factor changed by the experimenter.
  • Dependent variable: factor measured as a result of the independent variable.
  • Conclusion: states whether the hypothesis was correct based on experimental results.

Interpreting Data

• Scientific evidence is all data collected during an experiment.
• To interpret data, check if it answers the question and supports the hypothesis.
• If data aligns with the hypothesis, interpret it accordingly.

Types of Variables

• Independent variable: changed factor in an experiment.
• Dependent variable: measured outcome of the experiment.
• Controlled variables: factors kept constant throughout the experiment.
• Controls: standards to assess experimental validity.

Timelines

• Display events in chronological order.
• Examine the title to identify the topic.
• Note the time periods shown (days, months, years, decades, centuries).

Engineering Design Process

• Series of steps for solving problems.
• Steps include:
  • Ask
  • Research
  • Imagine
  • Select & Plan
  • Create
  • Test & Evaluate
  • Improve

Atoms

• Basic building blocks of matter.
• Composed of:
  • Nucleus (center): made of protons and neutrons.
  • Electrons: orbit the nucleus.

Electrons

• Negatively charged particles.
• Involved in electrical currents and bonding atoms.
• Number of electrons varies between elements.

Valence Electrons

• Electrons in the outermost shell (energy level) of an atom.
• Crucial for determining element combinations.
• Periodic table helps predict valence electron count (except for groups 3-12).
• Atoms strive for a full valence electron shell (8 is a common goal).

Molecules

• Groups of two or more atoms chemically bonded.
• Size and shape depend on the types and number of atoms.

Elements vs. Molecules vs. Compounds

• Elements consist of a single type of atom and cannot be broken down.
• Molecules are groups of atoms bonded together (can be the same or different atoms).
• Compounds are molecules made of different types of atoms.
• Molecules can be classified as ionic or covalent compounds.
• Pure substances contain only one type of compound or element.
• Mixtures contain two or more compounds or elements not chemically bonded.

Elements and the Periodic Table

• Elements are substances not further divisible.
• Periodic table organizes elements:
  • Element name
  • Atomic number (number of protons).
  • Symbol.
  • Atomic mass.
  • Category (metal, nonmetal, metalloid).
• Arrangement in periodic table helps determine basic element properties.
• Lightest elements are Hydrogen and Helium.
  Important elements used in organic molecules are Hydrogen, Carbon, Nitrogen, Oxygen Some important metals: Sodium, Gold, Silver, Iron, Copper, Aluminum Chlorine (Cl) is in table salt and Silicon (Si) is a metalloid used in various products.

Learn about the scientific method, a process for ensuring accurate scientific work, including steps like asking a question, research, prediction, experimentation, and result sharing. Understand experimental design components such as hypothesis, constants, independent and dependent variables, and conclusion.