The Scientific Method and Oceanography

THE SCIENTIFIC METHOD

  • Definition: The Scientific Method is an orderly and logical approach for gathering information that aids in solving problems.

Steps of the Scientific Method

  1. Make an Observation

    • Initial data collection or noticing phenomena.

  2. Get Curious & Ask a Question

    • Formulation of inquiries based on observations made.

  3. Form a Hypothesis

    • Definition: An educated guess; it serves as a tentative explanation for an observation.

  4. Test, Experiment, Gather Data, Etc.

    • Conduct experiments to either prove or disprove the hypothesis.

  5. Peer Review

    • Process where other experts evaluate the hypothesis and findings, ensuring validity and reliability.

  6. Propose a Law or Theory

    • Law: An explanation of observations supported by a large body of evidence that describes what is happening.

    • Theory: A broader explanation for why something happens, which can change with new observations and advancements in technology.

    • Example: Theory of Plate Tectonics & Continental Drift.

      • The Earth's crust is divided into large pieces known as plates that move due to convection.

      • Pangaea: Approximately 200 million years ago, all continents were part of this supercontinent, which has since split apart.

      • Movement of the plates occurs due to convection, which is the transfer of heat through circulation wherein hot materials rise and cold materials sink (less dense vs. more dense).

Types of Plate Boundaries

  1. Convergent Boundaries

    • Plates moving towards each other.

  2. Divergent Boundaries

    • Plates moving apart from each other.

  3. Transform Boundaries

    • Plates sliding past each other.

Types of Crust

  • Oceanic Crust

    • More dense, higher iron content, thinner (approximately 5 miles thick).

  • Continental Crust

    • Less dense, higher silica content, thicker (approximately 50 miles thick).

STRUCTURE OF THE OCEAN BOTTOM

  • Bathymetry: The study of ocean contours (topography).

  • The ocean is distinguished into two zones:

    • Continental Margin

    • The submerged outer edge of the continent (continental shelf).

    • Ocean Basin

    • The deeper part of the ocean beyond the margin.

Types of Margins

  • Passive Margins

    • Edges of continents that are far from a plate boundary, characterized by large shelves and beaches.

  • Active Margins

    • Located close to plate boundaries, resulting in smaller beaches, rocky coastlines, and geological activity like earthquakes and volcanoes.

Continental Slopes

  • Transition zone between the continental shelf and the ocean basin.

  • Submarine Canyons: Underwater ravines formed by turbidity currents, akin to underwater avalanches.

Features of the Ocean Basins

  • Ocean Ridges: Volcanic systems forming along divergent boundaries (e.g., mid-ocean spreading centers).

  • Seamounts and Guyots: Underwater mountains; seamounts never reached the surface, while guyots did but have since eroded.

  • Trenches: Depressions where one plate subducts beneath another.

  • Volcanic Island Arcs: Form as a result of subduction.

  • Abyssal Plains: Flat, featureless areas lying between trenches and ridges.

UNIQUE PROPERTIES OF WATER

  1. Electrostatic Bonding

    • Water (H2O) is slightly polar, enabling cohesion (water sticking to itself) and adhesion (water sticking to other materials).

    • Significance:

      • Water can dissolve land and gases, essential for ecological processes.

      • Example gases: CO2 (important for plants) and O2 (crucial for animals).

      • Cold water holds gases in solution more effectively.

      • Different components like oil and water do not mix.

  2. Hydrogen Bonds and Their Effects

    • Hydrogen bonds affect light and sound in bodies of water.

    • Photic Zone: The depth where sunlight penetrates; varies from deep in clear ocean water to shallow near shores.

    • Sound travels more easily in water than in air, allowing aquatic animals to utilize sound for navigation despite poor eyesight.

  3. Ice Floats

    • Water is unique in that it expands (about 9% of its volume) as it approaches freezing, becoming less dense, therefore ice floats.

    • As seawater freezes, salts are excluded, increasing the salinity of surrounding water.

    • Pycnoclines: Layers where density changes with depth; temperature changes cause materials to either expand or contract.

    • Thermocline: A graphical representation of temperature change with depth.

    • Halocline: A zone of rapid salinity increase with depth.

  4. Water Changes Phase

    • Definition of Terms:

      • Temperature: Measure of hotness or coldness.

      • Heat: A form of energy denoting the speed of molecular vibration.

    • Water can change phase via heat absorption or loss:

      • Evaporation: Liquid water becomes gaseous vapor, involving heat leaving the liquid to transition to a gaseous phase.

      • Condensation: Water vapor converts back to liquid, requiring a temperature drop allowing liquid formation as heat is released to the atmosphere.

      • Freezing and Melting: Ice melts due to solar heat, but water temperature remains unchanged during phase transitions (ice to liquid and vice versa).

    • Loss of heat in the air during phase changes plays a role in weather patterns.

  5. Water Moderates Temperature

    • High heat capacity (specific heat) means water takes longer to change temperature compared to land.

    • Specific Heat: Amount of energy required to change temperature. Water takes approximately five times longer to change temperature relative to land.

  6. Water Movement

    • Water can diffuse heat both vertically and horizontally through processes like convection and wind (advection).