Scientific Inquiry, Processes and Social Perspectives Summary

Scientific Inquiry Processes

• Representative Process of Inquiry:

  • Observation: Make an observation that is objective and capable of being duplicated by other scientists.
  • Information Gathering: Gather and evaluate all available information regarding the specific observation.
  • Hypothesis Formation: Create an educated guess or hypothesis to explain the cause of the observation; this hypothesis must be testable.
  • Experimentation: Conduct a rigorous experiment to test the proposed hypothesis.
  • Data Analysis and Reporting: Analyze the collected data and report whether the hypothesis was supported or not. Data should be shared with the scientific community.
  • Prediction: Formulate new predictions based on the results of the data analysis.

• Theory versus Law in Science:

  • Theory: Explains why various types of physical phenomena occur. A theory is the result of repeated testing by many researchers and has been found to be valid.
  • Law: Describes physical phenomena and the associated cause-and-effect relationships. It does not attempt to explain why phenomena behave as they do. Like theories, laws have been repeatedly tested and validated.

Experimental Design

• Bias and Validity:

  • Experiments must be conducted without bias toward a specific outcome.
  • If an experiment proves a hypothesis false, a new hypothesis is required, regardless of the elegance of the original idea.
  • Data analysis must remain objective and avoid bias toward expected results.

• Designing the Experiment:

  • Once a problem is identified and a hypothesis created, prior research should be used as a guide for design.
  • Control of Variables: To ensure results depend on a specific factor, only one variable should be varied at a time. All other quantities are designated as control variables and must remain constant.
  • Independent Variable: The specific variable that is intentionally altered.
  • Dependent Variable: The variable that changes or occurs based on the independent variable.

• Reproducibility:

  • Data must be shared with other experimenters. If others cannot reproduce the experiment and achieve the same results, the data cannot support the hypothesis until corrected.

Nature of Scientific Knowledge

• Foundation of Knowledge: Scientific knowledge is built upon questions answerable through experiment, detailed observation, or complex calculations.
• Models: Knowledge leads to the creation of models (theories and laws) which are used to make predictions about related, unobserved phenomena.
• Modification of Models: If predictions fail, models must be modified to accommodate new results.
• Unification: The most effective models unify separate observations. Example: Electromagnetic theory combined the previously separate principles of electricity and magnetism.
• Changeability: Scientific knowledge is always subject to change as more complete experiments occur. Example: Einstein’s Special Theory of Relativity modified Newton’s Three Laws for objects moving near the speed of light ($c$).

Physics Principles and Historical Figures

• Ancient Physics:

  • Aristotle: Proposed that observation of physical phenomena leads to explanations of how/why they occur.
  • Archimedes: Studied statics (the lever) and hydrostatics (buoyancy force).
  • Shen Kuo: Identified the magnetic compass needle.

• 17th Century:

  • Copernicus: Proposed the heliocentric model of the solar system.
  • Galileo: Contributions to astronomy, the experimental method, and the telescope.
  • Hooke: Discovered the cell; studied gravity and elasticity.
  • Newton: Formulated the Three Laws of Motion, universal gravitation, optics, and calculus; authored the Principia covering mechanics.

• 19th Century:

  • Young: Demonstrated the wave nature of light.
  • Dalton: Proposed atomic theory; stated all substances are made of indivisible atoms and all atoms of a specific substance are identical.
  • Faraday: Discovered electromagnetic induction and field theory to explain action at a distance.
  • Maxwell: Established the Theory of Electromagnetism on a mathematical footing (Maxwell's Equations); defined the nature of light.
  • Joule and Watt: Contributions to thermodynamics.

• 20th Century:

  • Einstein: Special Theory of Relativity, Photoelectric Effect, and General Theory of Relativity.
  • Planck: Formulated Quantum Theory and studied black-body radiation.
  • Curie and Becquerel: Research into radioactivity.
  • Thomson, Millikan, and Fletcher: Discovery of the electron and measurement of electron charge.
  • Schrodinger and Heisenberg: Development of Quantum Mechanics.
  • Meitner: Contributions to Nuclear Physics.
  • Particle Physics Contributors: Gell-Mann, Glashow, Weinberg, Tomonaga, Feynman, Salam, Kobayashi, Higgs, and others.

Chemistry Principles and Historical Figures

• 17th Century:

  • Boyle: Created the gas law stating the pressure of an ideal gas is inversely proportional to its volume at constant temperature ($P \times V = k$).

• 18th Century:

  • Lavoisier: Defined the Law of Conservation of Mass.
  • Coulomb: Established Coulomb’s Law, stating like charges repel and opposite charges attract.

• 19th Century:

  • Avogadro: Discovered the number of molecules in a $1$ gram mole sample: $6.02 \times 10^{23}$.
  • Dalton: Atomic theory (identical atoms for pure substances).
  • Gay-Lussac: Determined water consists of two parts hydrogen and one part oxygen ($H_2O$).
  • Mendeleev: Created the periodic table of elements.
  • Kelvin: Developed the concept of absolute zero.
  • Boltzmann: Distribution of molecular velocities in the gas phase.
  • Arrhenius: Developed ion theory to explain conductivity in electrolytes.
  • Le Chatelier: Formulated the principle explaining how dynamic chemical equilibria respond to external stresses.

• 20th Century:

  • Thomson, Millikan, and Fletcher: Electron discovery and charge measurement.
  • Bohr: Proposed discrete energy levels for electrons; stable orbits around the nucleus with jumps between levels.
  • Rutherford: Discovered that nearly the total mass of an atom is concentrated in the nucleus.
  • Lewis: Proposed the electron-pair concept for acids and bases.

Biology Principles and Historical Figures

• 16th Century:

  • Andreas Vesalius: Founder of modern anatomy; corrected misconceptions held for over a millennium.

• 17th Century:

  • Robert Hooke: Discovered cells and wrote Micrographia, revealing the microscopic world.
  • Antonie van Leeuwenhoek: Father of microbiology; used self-made lenses to discover bacteria, spermatozoa, and single-celled organisms.
  • William Harvey: Explained blood circulation as a complete circuit starting and ending at the heart.

• 18th Century:

  • Carolus Linnaeus: Created the binomial nomenclature system (two-part naming) for classifying life; classified approximately $13,000$ lifeforms, including humans.

• 19th Century:

  • Theodor Schwann: Established that the cell is the basic unit of all living things (foundation of modern histology); discovered pepsin; studied alcohol fermentation.
  • Gregor Mendel: Founder of genetics; identified rules of heredity, including dominant and recessive traits and mathematical predictability of inheritance.
  • Charles Darwin: Authored On the Origin of Species; proposed evolution by natural selection.
  • Alfred R. Wallace: Independently formulated the theory of evolution by natural selection; early advocate for environmental protection.
  • Louis Pasteur: Father of modern microbiology; discovered mirror-image molecules, anaerobic bacteria, and germ theory; invented pasteurization.

• 20th Century:

  • Maurice Wilkins: Initiated experimental DNA research; used X-ray images to identify the helical structure of DNA.
  • Rosalind Franklin: Provided critical experimental data for DNA structure; discovered DNA exists in two forms.
  • Francis Crick and James Watson: Co-discovered DNA's double-helix structure and replication; established the Sequence Hypothesis and Central Dogma; identified the triplet code for protein formation.
  • Ronald Fisher: Invented experimental design and the statistical concept of variance; unified natural selection with Mendelian genetics to create population genetics.
  • Stephen Jay Gould: Devised the theory of punctuated equilibrium (long stability broken by rapid change).
  • Barbara McClintock: Discovered chromosomal crossover and transposition ("jumping genes"); showed genes switch physical traits on/off.
  • Linus Pauling: Formulated valence bond theory and electronegativity; founded quantum chemistry and molecular biology; discovered protein alpha-helix; identified sickle-cell anemia as a molecular disease.
  • Carl Woese: Discovered Archaea as a third basic form of life using genetic analysis.
  • Rachel Carson: Environmentalist; authored Silent Spring, leading to restrictions on chemicals like DDT.

Data Collection, Analysis, and Sources of Error

• Data Organization:

  • Data should be collected in an organized manner.
  • Data should never be removed simply because it is believed to be incorrect, as later analysis might reveal unexpected events.
  • If data are proven incorrect, they are not presented but must be saved.
  • Raw and analyzed data should be presented in tables, charts, or graphs.

• The International System of Units (SI):

  • Length: meter ($m$)
  • Mass: kilogram ($kg$)
  • Time: second ($s$)
  • Current: Ampere ($A$)
  • Temperature: Kelvin ($K$)
  • Amount of Substance: mole ($mol$)
  • Light Intensity: candela ($cd$)
  • Exceptions: Experiment-specific units like nanometers ($10^{-9}\,m$) for wavelength in optics.
  • Derived Units: Combinations of base units, such as velocity ($m/s$) or force ($kg\,m/s^2$, known as the Newton, $N$).

• Significant Figures:

  • Includes all definite values plus one approximate value (the last digit).
  • Rules:
    1. Non-zero digits and zeros between non-zero digits are significant.
    2. Leading zeros (left of non-zeros) are not significant.
    3. Trailing zeros are significant only if a decimal point is present.
  • Calculations:
    • Multiplication/Division: Result has the same number of sig figs as the factor with the fewest.
    • Addition/Subtraction: Result has sig figs up to the right-most column where all numbers have a significant digit.

• Uncertainty and Error:

  • Propagation of Uncertainty: Uncertainty from measurement devices increases during calculations.
  • Procedural Errors: Not valid sources of error; the experiment must be repeated correctly.
  • Systematic Errors: Caused by improper tool use or poorly calibrated/damaged instruments. These affect accuracy (closeness to the accepted value).
  • Random Errors: Caused by environmental changes or instrument fluctuations. These affect precision (consistency among multiple measurements).

Lab Techniques and Safety

• General Protocols:

  • A written procedure for lab techniques and safety must be available and understood by all personnel.
  • Constant supervision is mandatory.
  • Report all injuries or illnesses immediately to the instructor.
  • No dangling jewelry or headphones are allowed.
  • Instructor demonstration is required before students attempt experiments.
  • Any deviation from procedure requires prior instructor approval.

• Equipment and Environment:

  • Equipment must be checked frequently; electrical safety is critical.
  • Safety equipment includes fume hoods, fire extinguishers, fire blankets, eyewash/shower stations, and first aid kits.
  • Equipment should only be plugged in after inspection and instructor permission.
  • All equipment must be returned to storage after use.

Science, Technology, and Societal Impact

• Benefits and Risks:

  • Nanotechnology: Used for repairing human tissue, solar energy efficiency, and targeted drug delivery.
  • Pharmacology: Chemistry helps determine drug interactions and synthesize pharmaceuticals.
  • Environmental Issues:
    • Acid Rain: Caused by the release of sulfur dioxide and nitrogen oxides into the air.
    • Air Pollution: Particulates, harmful gases, or biological molecules in the atmosphere.
    • Water Pollution: Foreign objects or chemicals in aquatic ecosystems.
    • Greenhouse Effect: Radiation from the atmosphere warming the Earth’s surface.
    • Ozone Depletion: Halogen radicals act as catalysts in breaking down ozone.
    • Chemical Recycling: Reducing polymers to monomers to create new plastics.

• Energy Use and Production:

  • Renewable Sources: Hydropower, geothermal, biomass, wind, and solar.
  • Non-renewable Sources: Oil, gas, coal, and uranium.
  • Trade-offs: Hydropower is clean but can displace communities. Wind and solar are clean but inconsistent. Fossil fuels are reliable and efficient but cause air pollution and increase $CO_2$ levels.

Daily Applications of Science

• Chemistry Applications:

  • Water Purification: Chlorination, ozonation, and chemical neutralization.
  • Soaps: Salt compounds of fatty acids that emulsify dirt and oil using their molecular structure.
  • Plastics: Created through polymerization, forming chains or networks of atoms called polymers.
  • Batteries: Electrochemical cells storing chemical energy for later conversion to electricity.
  • Fuel Cells: Convert chemical energy from fuel into electricity via reaction with an oxidizing agent.
  • Baking Soda (Sodium Bicarbonate): Produces $CO_2$ through chemical reaction to help dough rise.

• Physics Applications:

  • Communications: Utilizes transistors, lasers (fiber optics), and wireless EM waves.
  • Medicine: Lasers for surgery, X-rays and MRI (magnetic resonance imaging) for diagnosis, and Gamma rays to kill cancer cells.
  • Transportation: GPS satellites for routing and magnetic levitation for high-speed trains (reduces friction).
  • Power Grid: Built on power generation, electromagnetic induction, AC circuits, and transformers.