Overview
This lecture provides a comprehensive review of key GED Science concepts, including scientific method, biology, chemistry, physics, earth and environmental science, with practice questions and explanations of correct answers.
Scientific Method and Variables
- The scientific method includes observation, hypothesis, experimentation, data analysis, conclusion, and communication.
- Experimentation involves manipulating variables to test hypotheses.
- Independent variable: manipulated by the experimenter; Dependent variable: measured outcome affected by the independent variable.
- In an egg hatching experiment, temperature is the independent variable and hatching time is the dependent variable.
Graphs, Units, and Conversions
- The x-axis shows the independent variable; the y-axis the dependent variable.
- Use provided conversion factors for units (e.g., miles/hour × 1.609 = km/hour).
- To convert Fahrenheit to Celsius: ( C = (F - 32) \times 5/9 ).
Biology: Characteristics of Life and Cells
- Seven characteristics of living organisms: organization, energy use, homeostasis, growth, reproduction, adaptation, response to stimuli.
- Properties of life are shown through these characteristics (e.g., metabolism differs in fish and birds).
- Major animal cell organelles to recognize: nucleus (controls genetic info), cell membrane (controls substance movement), mitochondria, etc.
- White blood cells (leukocytes) produce antibodies; red blood cells transport oxygen.
Genetics and Heredity
- Traits can be controlled by single or multiple genes; environment can also influence traits.
- Tongue rolling is a classic example of a single-gene trait with dominant/recessive alleles.
- Terms: heterozygous (two different alleles), homozygous dominant (two dominant), homozygous recessive (two recessive).
- Use Punnett squares to predict offspring probabilities.
Evolution and Natural Selection
- Natural selection: individuals with advantageous traits are likelier to survive and reproduce.
- Example: Galapagos finches' beak size changes due to food source.
- Adaptation can eventually lead to new species.
Ecology and Classification
- Food chains: producers (plants), primary consumers (herbivores), secondary consumers (carnivores), tertiary/quaternary consumers.
- Taxonomy organizes organisms by evolutionary relationships; basic classes include fish, birds, amphibians, insects, reptiles.
- Pie charts can visualize population distributions.
Human Anatomy and Physiology
- Circulatory system: transports materials; respiratory system: gas exchange; immune system: defends against disease.
- Voluntary muscles are consciously controlled; involuntary muscles operate automatically.
- Bacteria can reproduce independently; viruses require a host.
Chemistry: Matter and Atomic Structure
- Density = mass/volume.
- Sublimation: solid to gas phase change.
- Physical properties: density, color, texture; chemical properties: flammability, reactivity.
- Atomic number = number of protons.
- Elements in the same periodic table group have similar chemical properties.
- Protons and neutrons are in the nucleus; electrons orbit outside.
Chemical Bonding and Equations
- Chemical equations must be balanced (same number of each atom on both sides).
- Example: ( 2H_2 + O_2 \rightarrow 2H_2O ).
- Practice balancing equations and identifying coefficients.
Physics: Mechanics, Gas Laws, Waves, and Electricity
- Potential energy lost = kinetic energy gained (e.g., rolling ball down ramp).
- Ideal gas law: ( PV = nRT ); doubling pressure doubles temperature if volume and moles are constant.
- Wave speed: ( v = f \lambda ).
- Ohm’s law: ( V = IR ).
Earth and Space Science
- Iron oxide causes red rock coloration in canyons and on Mars.
- Igneous rocks form from cooled magma/lava; sedimentary from deposited particles; metamorphic from transformed rocks.
- Know distinguishing features of planets and rock types.
Environmental Science and Sustainability
- Climate change is mainly caused by increased greenhouse gas emissions.
- Rising sea levels threaten coastal communities due to melting ice and ocean expansion.
- Sustainable development uses resources for current needs while protecting future generations.
Key Terms & Definitions
- Scientific Method — step-by-step approach to investigating phenomena.
- Independent Variable — variable changed by experimenter.
- Dependent Variable — outcome measured in an experiment.
- Homeostasis — maintaining internal stability.
- Metabolism — chemical processes sustaining life.
- Genotype — genetic makeup.
- Phenotype — observable characteristics.
- Natural Selection — survival and reproduction of certain traits.
- Taxonomy — classification of living things.
- Density — mass divided by volume.
- Sublimation — solid to gas transition.
- Atomic Number — number of protons in an atom.
- Ohm’s Law — relationship between voltage, current, and resistance.
Action Items / Next Steps
- Review major organelles and their functions.
- Practice unit conversions and balancing chemical equations.
- Study food chains and classification systems.
- Memorize major human body systems and their primary functions.
- Complete all assigned readings and additional practice problems.