Physical Science Unit 1 Review: Introduction to Physical Science

Key Concepts and Terminology

• Physical science studies non-living systems in the universe encompasses physics, chemistry, astronomy, and earth science
• Matter anything that has mass and takes up space categorized as solid, liquid, gas, or plasma
• Energy ability to do work or cause change exists in many forms (kinetic, potential, thermal, electrical, chemical, nuclear)
  • Kinetic energy energy of motion depends on mass and velocity
  • Potential energy stored energy due to an object's position or configuration (gravitational, elastic, chemical)
• Atom smallest unit of matter consists of protons, neutrons, and electrons
  • Proton positively charged particle located in the nucleus
  • Neutron neutral particle located in the nucleus
  • Electron negatively charged particle orbiting the nucleus in shells
• Periodic table organizes elements based on atomic number and chemical properties arranged in rows (periods) and columns (groups)
• Chemical reaction process where substances change into different substances with different properties (reactants → products)

Scientific Method and Inquiry

• Scientific method systematic approach to acquiring knowledge involves making observations, formulating hypotheses, testing predictions, and developing theories
  1. Observation: Gathering information and data through senses or measurements
  2. Question: Asking a question based on observations
  3. Hypothesis: Proposing a tentative explanation that can be tested
  4. Experiment: Designing and conducting a controlled test to validate or refute the hypothesis
  5. Analysis: Examining the results and drawing conclusions
  6. Publication: Sharing findings with the scientific community for peer review
• Controlled experiment tests a single variable by keeping other variables constant (control vs. experimental group)
• Independent variable manipulated factor in an experiment (cause)
• Dependent variable measured factor in an experiment (effect)
• Scientific theory well-substantiated explanation of natural phenomena based on facts, laws, and tested hypotheses (evolution, relativity)
• Scientific law concise statement that describes a relationship in nature without explaining why it exists (Newton's laws of motion)
• Peer review process where scientific work is evaluated by experts in the same field ensures quality and accuracy

Matter and Energy Basics

• Conservation of mass principle stating that matter cannot be created or destroyed in a chemical reaction (reactant mass = product mass)
• Conservation of energy principle stating that energy cannot be created or destroyed, only converted from one form to another
• Phase change physical process where matter changes between solid, liquid, and gas without altering its chemical composition
  • Melting: Solid → Liquid (increases kinetic energy)
  • Freezing: Liquid → Solid (decreases kinetic energy)
  • Vaporization: Liquid → Gas (increases kinetic energy)
  • Condensation: Gas → Liquid (decreases kinetic energy)
• Heat transfer flow of thermal energy from a warmer object to a cooler object (conduction, convection, radiation)
  • Conduction: Transfer through direct contact (touching a hot stove)
  • Convection: Transfer through fluid motion (hot air rising)
  • Radiation: Transfer through electromagnetic waves (sunlight warming the Earth)
• Temperature measure of average kinetic energy of particles in a substance (Celsius, Fahrenheit, Kelvin scales)
• Specific heat capacity amount of heat required to raise the temperature of 1 gram of a substance by 1°C depends on the material

Forces and Motion

• Force push or pull on an object can cause a change in motion (acceleration), shape (deformation), or both
• Newton's first law (inertia) objects at rest stay at rest, and objects in motion stay in motion with constant velocity unless acted upon by an unbalanced force
• Newton's second law (F=ma) force equals mass times acceleration; greater mass requires greater force for same acceleration
• Newton's third law (action-reaction) for every action, there is an equal and opposite reaction (rocket propulsion)
• Friction force that opposes motion between two surfaces in contact (static vs. kinetic)
  • Static friction: Force preventing an object from starting to move
  • Kinetic friction: Force opposing an object's motion once it starts moving
• Gravity attractive force between any two masses; strength depends on masses and distance (inverse square law)
• Velocity speed and direction of an object's motion (vector quantity)
• Acceleration rate of change of velocity can be positive (speeding up), negative (slowing down), or zero (constant velocity)
• Momentum product of an object's mass and velocity (p=mv); conserved in closed systems during collisions

Waves and Electromagnetic Spectrum

• Wave disturbance that transfers energy through matter or space without transferring matter (mechanical vs. electromagnetic)
  • Mechanical wave: Requires a medium to propagate (sound waves, water waves)
  • Electromagnetic wave: Can travel through a vacuum (light, radio waves, X-rays)
• Wavelength distance between two consecutive crests or troughs of a wave
• Frequency number of waves passing a fixed point per unit time (Hertz)
• Amplitude maximum displacement of a wave from its equilibrium position
• Electromagnetic spectrum range of all possible electromagnetic radiation frequencies (radio waves → microwaves → infrared → visible light → ultraviolet → X-rays → gamma rays)
  • Radio waves: Longest wavelength, lowest frequency (communication, astronomy)
  • Microwaves: Shorter wavelength than radio waves (cooking, radar)
  • Infrared: Longer wavelength than visible light (thermal imaging, remote controls)
  • Visible light: Narrow range of wavelengths detectable by human eye (RGB colors)
  • Ultraviolet: Shorter wavelength than visible light (sunburn, disinfection)
  • X-rays: Shorter wavelength than ultraviolet (medical imaging, airport security)
  • Gamma rays: Shortest wavelength, highest frequency (nuclear medicine, astronomy)
• Doppler effect apparent change in frequency of a wave due to relative motion between source and observer (ambulance siren)

Earth and Space Science Fundamentals

• Earth's structure consists of crust, mantle, outer core, and inner core
  • Crust: Thin, rocky outer layer (oceanic vs. continental)
  • Mantle: Thick, semi-solid layer below the crust (convection currents)
  • Outer core: Liquid layer composed primarily of iron and nickel
  • Inner core: Solid layer at the center, extremely high pressure and temperature
• Plate tectonics theory that Earth's lithosphere is divided into plates that move and interact (convergent, divergent, transform boundaries)
  • Convergent boundary: Plates collide, causing subduction or mountain building (Andes, Himalayas)
  • Divergent boundary: Plates move apart, creating new crust (mid-ocean ridges, East African Rift)
  • Transform boundary: Plates slide past each other (San Andreas Fault)
• Rock cycle continuous process of rock formation and transformation (igneous → sedimentary → metamorphic)
  • Igneous rock: Formed from cooled magma or lava (granite, basalt)
  • Sedimentary rock: Formed from compacted and cemented sediments (sandstone, limestone)
  • Metamorphic rock: Formed from pre-existing rocks subjected to heat and pressure (marble, gneiss)
• Water cycle continuous movement of water on, above, and below Earth's surface (evaporation, condensation, precipitation, runoff)
• Greenhouse effect trapping of heat by atmospheric gases (carbon dioxide, methane) leading to warming of Earth's surface
• Solar system consists of the Sun, eight planets, dwarf planets, moons, asteroids, comets, and meteoroids
  • Terrestrial planets: Rocky, inner planets (Mercury, Venus, Earth, Mars)
  • Jovian planets: Gaseous, outer planets (Jupiter, Saturn, Uranus, Neptune)
• Stellar evolution life cycle of a star, from formation to death (nebula → protostar → main sequence → red giant → white dwarf/supernova)
  • Nebula: Cloud of gas and dust, birthplace of stars
  • Protostar: Contracting core of a nebula, not yet fusing hydrogen
  • Main sequence: Stable phase where star fuses hydrogen into helium (Sun)
  • Red giant: Expanded, cooler phase after main sequence (Aldebaran)
  • White dwarf: Hot, dense remnant of a low-mass star (Sirius B)
  • Supernova: Explosive death of a high-mass star, leaves behind a neutron star or black hole (Crab Nebula)

Lab Techniques and Safety

• Scientific notation concise way to express very large or very small numbers using powers of 10 (6.02 × 10²³)
• Significant figures digits in a measured value that are known with certainty plus one estimated digit
• Precision degree of agreement among repeated measurements (reproducibility)
• Accuracy degree of closeness between a measured value and the true value
• Measurement uncertainty quantification of the doubt in a measured value, often expressed as a range (±)
• Lab safety practices:
  • Wear personal protective equipment (goggles, gloves, lab coat)
  • Handle chemicals and equipment with caution
  • Read and follow lab procedures carefully
  • Dispose of waste properly
  • Know the location of safety equipment (fire extinguisher, eyewash station, shower)
• Microscope instrument used to magnify small objects (compound vs. stereo)
  • Compound microscope: Uses multiple lenses to achieve high magnification (400×)
  • Stereo microscope: Uses two separate optical paths to provide a 3D view (dissection)
• Spectroscopy techniques that use the interaction of matter and electromagnetic radiation to identify substances (absorption, emission, Raman)
  • Absorption spectroscopy: Measures the wavelengths of light absorbed by a sample
  • Emission spectroscopy: Measures the wavelengths of light emitted by a sample
  • Raman spectroscopy: Measures the wavelength shifts caused by inelastic scattering of light

Real-World Applications

• Renewable energy sources that can be replenished naturally (solar, wind, hydro, geothermal, biomass)
  • Solar energy: Harnessing energy from the Sun (photovoltaic cells, solar thermal)
  • Wind energy: Harnessing kinetic energy from moving air (wind turbines)
  • Hydropower: Harnessing energy from moving water (dams, tidal)
  • Geothermal energy: Harnessing heat from the Earth's interior (power plants, heating)
  • Biomass energy: Harnessing energy from organic matter (wood, biofuels)
• Nanotechnology manipulation of matter at the atomic and molecular scale (1-100 nm)
  • Carbon nanotubes: Cylindrical carbon molecules with unique properties (strength, conductivity)
  • Nanorobotics: Designing and building machines at the nanoscale (drug delivery, manufacturing)
• Biotechnology use of living organisms or their products for commercial or industrial purposes (genetic engineering, bioremediation)
  • Genetic engineering: Modifying the DNA of organisms to introduce desired traits (pest-resistant crops, insulin production)
  • Bioremediation: Using microorganisms to clean up contaminated environments (oil spills, wastewater treatment)
• Medical imaging techniques that allow visualization of internal body structures (X-ray, CT, MRI, ultrasound)
  • X-ray: Uses high-energy electromagnetic waves to create 2D images of dense tissues (bones, teeth)
  • Computed tomography (CT): Uses X-rays from multiple angles to create 3D images of soft tissues
  • Magnetic resonance imaging (MRI): Uses strong magnetic fields and radio waves to create detailed images of organs and tissues
  • Ultrasound: Uses high-frequency sound waves to create real-time images (fetal development, heart function)
• Space exploration efforts to study the universe beyond Earth (telescopes, probes, rovers, human missions)
  • Hubble Space Telescope: Orbiting observatory that captures high-resolution images of distant objects
  • Mars rovers: Robotic vehicles that explore the surface of Mars (Curiosity, Perseverance)
  • International Space Station (ISS): Habitable artificial satellite for scientific research and international cooperation
  • Artemis program: NASA's initiative to return humans to the Moon and establish a sustainable presence