Scientific Method and Experimental Design Quiz

Scientific Method

• A series of steps used by scientists to answer questions about the world.
• Steps may vary depending on the experiment and discipline.
• Steps include: question, background research, hypothesis, experiment, data analysis, conclusion.
• Supported hypotheses may become theories.
• Biases can invalidate experiments.

Experimental Design

• An invaluable process in science to support or refute hypotheses.
• Begins with an observation leading to a question and informed hypothesis.
• Five steps: variable definition, hypothesis formulation, experimental design, subject assignment, dependent variable measurement.
• Careful research and completion of five steps are crucial for good experiments.

Scientific Vocabulary

• Much scientific vocabulary originates from Greek and Latin.
• Greek used by early scientists.
• Latin often used in naming organisms due to universality.
• Word parts (prefixes, roots, suffixes) and morphemes aid understanding.
• Root is the primary word part; prefix precedes, suffix follows.

Learning Styles

• Auditory (learning by hearing).
• Visual (learning by sight).
• Hands-on (learning by doing).
• Holistic (building on prior knowledge).
• Analytic (breaking concepts into parts).

Matter

• Anything that has mass and takes up space.
• Has physical and chemical properties.
• Physical properties don't change composition (color, mass, density).
• Chemical properties relate to changes in composition (pH, reactivity).
• Corrosion (e.g., rusting) is a destructive chemical property.
• Matter types: pure substances (elements and compounds), mixtures.

States of Matter

• Four common states: solid, liquid, gas, plasma.
• Solid: low energy, high density, definite volume and shape (e.g., ice).
• Liquid: moderate energy, moderate density, definite volume, indefinite shape (e.g., water).
• Gas: high energy, low density, indefinite volume and shape (e.g., water vapor).
• Plasma: extremely high energy, low density, indefinite volume and shape (e.g., lightning).
• Matter can transition between states (melting, freezing, condensation, evaporation, sublimation, deposition, ionization, deionization).

Atoms

• The smallest unit of matter retaining element properties.
• Elements are substances of the same atom type.
• Elements defined by atomic number (number of protons).
• Protons: positively charged subatomic particles (1 amu), in the nucleus.
• Neutrons: neutral subatomic particles (1 amu), in the nucleus.
• Electrons: negatively charged subatomic particles orbiting the nucleus.
• Electrons participate in chemical reactions and bonding.

Electron Clouds and Subshells

• Electrons located in electron clouds (generalized regions).
• Electron clouds contain subshells (s, p, d, f).
• Electrons at different energy levels (7).
• Inner levels hold lower energy electrons.
• Outermost electrons are valence electrons, determining atom properties.
• Valence electron number given by group number on periodic table.
• Atoms tend to have full valence shells of 8 electrons.

Subatomic Particles

• Atoms contain protons, neutrons, and electrons.
• Proton: positively charged, 1 amu, nucleus.
• Neutron: no charge, 1 amu, nucleus.
• Electron: negatively charged, no mass, outside nucleus.
• Atomic number (Z): number of protons (same for all atoms of an element).
• Mass number (A): number of protons and neutrons.
• Isotopes: atoms of same element with different neutron counts.
• Atomic mass: weighted average of isotope masses.

Elements and the Periodic Table

• All matter is made of elements (pure substances, indivisible by chemical means).
• Elements organized on the Periodic Table.
• Atomic number = number of protons and electrons.
• Periodic Table arrangement by periods (rows) and groups (columns).
• Elements categorized as metals, nonmetals, or metalloids.
• Periodic Table trends identify element properties (valence electrons, atomic radius, ionization energy, electronegativity).

Molecules, Compounds, and Elements

• Atoms form molecules by sharing, gaining, or losing electrons.
• Molecules are one or more elements.
• Simple molecules (few atoms, covalent bonds), complex molecules (combination of simple molecules).
• Compound: pure substance of two or more different elements chemically bonded.
• All compounds are molecules, but not all molecules are compounds.

Endocytosis and Exocytosis

• Endocytosis: importing molecules/particles into the cell by membrane folding.
• Phagocytosis (nonspecific, "eating").
• Pinocytosis (nonspecific, "drinking").
• Receptor-mediated endocytosis (specific).
• Caveolae (non-clathrin based).
• Endocytosed substances can fuse with lysosomes for digestion.
• Exocytosis: secreting material outside the cell via vesicle fusion with membrane.
• Exocytosis releases undigested material, new material, and membrane components.

Photosynthesis

• Process in plant chloroplasts turning light energy into food.
• Two processes: light-dependent reaction (ATP/NADPH production, oxygen release in thylakoid); Calvin cycle (glucose production in stroma).
• Chloroplasts structure (DNA, stroma, ribosomes, chlorophyll, membranes, granum, thylakoid, lamella, lumen).
• Thylakoids house light-dependent reactions.
• Chlorophyll absorbs specific light wavelengths.
• Stroma provides volume.

Plant Cells: Vacuoles and Cell Walls

• Plant cells have vacuoles for water storage, waste elimination.
• Central vacuoles maintain turgor pressure.
• Cell walls, made of cellulose, provide strength and flexibility.
• Turgor pressure develops in hypotonic environments.
• Vacuoles lose water in isotonic or hypertonic environments, impacting cell shape.