Understanding the Scientific Method

Nature of Science

• Scientific Method Steps (with examples):

  • Observation: Why do plants grow taller in sunlight compared to shade?
  • Question: Why do plants grow taller in sunlight compared to shade?
  • Background Research: Research the role of sunlight in a plant's growth.
  • Hypothesis: If a plant receives more sunlight, then it will grow taller because sunlight provides energy for photosynthesis.
  • Experiment: Plant growth in inches over a time period with and without sunlight to test the hypothesis.
  • Data Collection & Analysis: Measure the amount of inches grown.
  • Conclusion: The plant in sunlight grew 7 cm taller than the plant without sunlight.
  • Communication: Share results with the class.

• Hypothesis Characteristics:

  • Testable
  • Falsifiable
  • Based on evidence
  • Logical
  • Specific
  • Repeatable

• Controlled Experiments and Controls:

  • Controlled experiments help determine if the independent variable truly causes the change.
  • Controls isolate potential confounding variables

• Graphing:

  • Title: Includes variables, units, and description.
  • Axes: Dependent variable (y-axis), Independent variable (x-axis).
  • Line graph: Used for tracking change over time.

• Control vs. Experimental Groups and Constants:

  • Control group: not changed, experimental group: is changed.
  • Constants: conditions kept the same.

• Procedure Importance: Reading experimental procedures ensures safety and accurate data collection.

• Error:

  • Experimental Error: Problems during the experiment itself.
  • Human Error: Mistakes made by individuals conducting the experiment.
  • Both are important to account for.

• Communication: Sharing results allows for accuracy checks and evaluation. Data should not be manipulated.

• Inference vs. Direct Observation:

  • Inference uses prior knowledge to guess an outcome.
  • Direct observation records factual data.

• Qualitative vs. Quantitative Data:

  • Qualitative: non-numeric data (descriptions).
  • Quantitative: data expressed in numbers.

Ecology

• Biosphere: Earth's life-supporting region.

• Biomes: Large ecosystems determined by climate and organisms.

• Ecosystem Components:

  • Biotic: Living (plants, animals, decomposers).
  • Abiotic: Nonliving (temperature, water, sunlight).

• Temperate Forest Biome:

  • Deciduous trees (lose leaves seasonally).
  • Common animals: deer, foxes, birds.

• Ecosystem Organization (Simplest to Most Complex):

  • Organism
  • Population
  • Community
  • Ecosystem
  • Biome
  • Biosphere

• Energy Transfer Roles:

  • Autotrophs (Producers): Make their own food (photosynthesis/chemosynthesis).
    • Chemosynthetic: Use chemicals as energy source.
    • Photosynthetic: Utilize sunlight.

• Heterotrophs (Consumers):

  • Primary Consumers: Herbivores.
  • Secondary Consumers: Carnivores or omnivores.
  • Tertiary Consumers: Top predators.

• Decomposers: Break down dead organic matter; fungi and bacteria.

• Trophic Levels: Levels in the food chain/web with the flow of energy.

  • Producers (most energy)
  • Primary Consumers
  • Secondary Consumers
  • Tertiary Consumers
  • Decomposers.

• Energy Pyramid: Energy decreases at higher trophic levels.

• Original Energy Source in Pond Ecosystem: Sunlight.

• Energy Transfer Percentage: 10%

• Predator: Organism that hunts and consumes others. Lowest trophic level: 2nd

Biochemistry

• Elements: Basic substances cannot be broken down.

• Common Elements in Organisms: Oxygen, carbon, hydrogen, nitrogen.

• Chemical Reactions: Reactants (substrates) → Products.

• pH Scale: Measures acidity; acids <7, bases >7.

• Solutions: Mixtures with solute dissolved in solvent.

  • Solute: Dissolved substance
  • Solvent: Dissolving substance

• Solvent in Blood/Cells: Water.

• Monomers and Polymers:

  • Monomers: Small units
  • Polymers: Constructed from monomers.

• Dehydration Synthesis: Builds molecules.

• Hydrolysis: Breaks molecules apart.

• Carbohydrates: Contain C, H, O.

  • Monomers: Monosaccharides.
  • Polymers: Polysaccharides (energy storage/structure), Disaccharides (energy).
  • Function: Cell fuel.

• Lipids: Fats, oils, hydrophobic.

  • Phospholipids: Form cell membranes.
  • Hydrophilic vs. Hydrophobic: Water-loving vs. water-fearing.

• Proteins: Made of amino acids.

  • Enzymes: Catalysts (speed up chemical reactions); reusable.
    • Active site: Location of enzymatic activity.
    • Activation Energy: Lowered by enzymes.
    • Denaturation: Loss of structure and function due to changes in pH/temp.

• Nucleic Acids: Carry genetic information— DNA and RNA.

  • Monomer: Nucleotides.
  • Genes: DNA segments, fuel currency— ATP

CELLS/CELL TRANSPORT (HOMEOSTASIS)

• Cell Theory:

  • All living things are made of cells
  • Cells are the basic unit of life
  • Cells come from pre-existing cells.

• Cell Necessities: Nutrients (building blocks), oxygen (energy).

• Cell Size Limits: Surface area-to-volume ratio (SA/Vol). Larger SA/Vol is better.

• Eukaryotic vs. Prokaryotic Cells:

  • Eukaryotes: nucleus, membrane-bound organelles
  • Prokaryotes: no nucleus, no organelles.

• Common Cell Parts: Cell membrane, nucleus, cytoplasm, mitochondria, endoplasmic reticulum, golgi apparatus, ribosomes, and cytoskeleton.

• Plant Cell Unique Parts: Cell wall, chloroplasts, vacuole.

• Endosymbiotic Theory: Mitochondria and chloroplasts were once free-living prokaryotes.

• Organelle Evolution:

  • Mitochondria: aerobic prokaryote
  • Chloroplasts: cyanobacterium

• Cell Transport:

  • Selective Permeability: Cell membrane lets certain substances pass through.

• Passive vs. Active Transport:

  • Passive Transport: No energy required, movement with the concentration gradient
  • Active Transport: Energy required, movement against the concentration gradient.

• Concentration Gradient: Difference in concentration between two areas.

  • 'Down' the gradient: high to low concentration
  • 'Against' the gradient: low to high concentration.

• Diffusion & Osmosis:

  • Osmosis: Water moves from low to high solute concentration, across a membrane.
  • Tonicity: Relative solute concentration in a solution.
    • Hypertonic: Higher solute concentration outside the cell.
    • Hypotonic: Lower solute concentration outside the cell.
    • Isotonic: Equal solute concentration inside and outside the cell.
    • Effects of each on water movement in/out of cells, and role of a cell wall.

• Facilitated Diffusion: Passive transport using proteins to help molecules move across the membrane

  • Aquaporins, ion channels, carrier proteins.

• Active Transport: Membrane pumps move substances against their concentration gradient, requiring energy.

Photosynthesis

• Autotrophs: Produce their own food— utilize energy from the sun.

• Photosynthesis Process: Plants convert sunlight, CO2, and H2O into glucose and O2.

• Photosynthesis Location: Leaves.

• Gas Exchange: Stomata (pores).

• Light Reactions Product: Oxygen.

• Carbon Source: Carbon dioxide.

• Chlorophyll: Absorbs light; reflects green light.

• Chloroplast Structure:

  • Thylakoids: Light-dependent reactions occur here.
  • Stroma: Light-independent (Calvin cycle) reactions occur here.

• Light-Dependent Reactions Inputs and Outputs:

  • Inputs: Water, light, inorganic phosphate, NADP+, ADP
  • Outputs: Oxygen, NADPH, ATP

• Light-Independent (Calvin Cycle) Reactions: Convert inorganic CO2 into organic compounds.

• Products: G3P, ADP, NADP+

• Calvin Cycle Location: Stroma

• G3P: Glyceraldehyde-3-phosphate.

This quiz explores the essential steps of the scientific method, including observation, hypothesis formation, and controlled experiments. Test your knowledge on how to conduct experiments and analyze results while ensuring your hypotheses are testable and repeatable. Perfect for students looking to solidify their understanding of scientific inquiry.