GHSGT Review for the Physical Science Domains

1. GHSGT Review for the Physical Science Domains Atoms, elements, bonding, compounds, mixtures, periodic table, Newtons Laws, Force, Work and Mechanical advantage, Heat transfer, Radioactivity, Electricity and Magnetism, Waves, Sound and Light

2. What is Matter? • Everything in the universe is either matter or energy • Matter has mass and takes up space (volume) • Mass is a measure of inertia • Space L x W x H • Either Pure substance of Elements or Compounds or mixtures of elements and compounds • Element- defined by number of protons in nucleus • Compound- two or more atoms of elements combined chemically (ionic or covalent)

3. Pure Substances • Elements – number of protons in nucleus of the atom 109 metal or nonmetal • Compounds – chemically combined by loosing (+) gaining (-) or sharing electrons Ions • Ionic bonding – electron transfer from metal (+) to nonmetal (-) Ca²+ O²- CaO • Group1 A.M.(1+) Group2 A.E.M. (2+) Group3-12 T.M.(1+ to 4+) Boron (3+) • Carbon (4+-) Nitrogen (3-) Oxygen (2- • Halogens (1-) Noble Gases stable octect

4. Formula for Compounds • Sum of the oxidation numbers must be O • Cross Multiply and use subscripts to balance • Na 1+ F 1- NaF • Ca 2+ F 1- CaF2 • Na 1+ O 2- Na2O • Al 3+ O 2- Al2O3

5. Mixtures • Heterogeneous – can distinguish phases • Homogeneous – solute is dissolved in the solvent Solid, Liquid or Gas • Colloid – heterogeneous mixture where the different phases are held in suspension Tyndall Effect • Physical Change – chemical properties remain the same change of state • Chemical Change – chemical reaction rearrangement of atoms new material with new properties endothermic or exothermic • Physical Properties include color, density, state • Chemical Properties include reactivity

6. Atomic Structure • Atom – smallest unit an element with characteristics of that element • Nucleus and an Electron Cloud mostly empty space • Nucleus – protons and neutrons mass of the atom mass number of amu’s • protons are the atomic number and identify the element • Isotopes – different number of neutrons • Electron Cloud – electrons occur at different energy levels filling lower levels first 2-8-18-32 divided up into sublevels • Outermost electrons are Valence electrons that are lost, gained or shared during bonding

7. Periodic Table is organized by the electron configuration of elements • Groups or Families have the same number of valence electrons • Each Period is filling that energy level • ex: 3 valence e- in the third energy level • Al 3+ oxidation • another ex: 2 valence e- in second • has to be Be • one more ex: 7 valence e- in the 2

8. Radioactivity • Radioactivity – spontaneous decay of unstable nuclei Strong and Weak nuclear forces • Unstable because of the proton/neutron ratio 1:1 small elements 2:3 larger atom • radioactive isotopes go through series to become stable releasing alpha, beta and (particles) and gamma (pure energy) • Alpha decay – 4amu’s 2p 2n He nucleus • produces another element strong nuclear • ex: unstable U-234 undergoes alpha decay U-234 yields He²+ and Th-230

9. Beta decay – high energy electron emitted from neutron weak nuclear force • also changes the element by converting a neutron into a proton mass is the same • ex: C-14 to N-14 • Gamma does not change the identity, but does release energy E=mc²

10. What is Energy and how is Energy used? • Energy is the ability to cause a change or to do work • 6 forms – mechanical, electric, thermal, nuclear, radiant and chemical • Mechanical energy is energy of motion • Motion – change of position relative to a frame of reference • motion takes place at a certain speed or velocity • Speed is rate of change in position rate=time • speed=distance/time velocity=displacement/time

11. speed can be constant, changing, instantaneous or the average is calculated • constant=straight line curve, changing ? Instantaneous=point, average=total t/dis • Acceleration is rate of change of displacement • Acc = Δd/Δt a=df-di/tf-ti m/s/s or m/s² • Acceleration is the result of an unbalanced force • Force – push or pull against a mass • Mass – measure of Inertia • Inertia – resistance to acceleration 1st Law • Newton’s Laws 1st inertia 2nd F=ma

12. 3rd action-reaction F=ma kg m/s² newtons of force • friction – force that opposes motion • static rolling sliding • lubricants push surfaces apart to reduce friction • Air resistance – air friction of falling objects • all things fall at the same rate in a vacuum because of balance of gravity and inertia • Gravity – force of attraction(?) between all objects F=ma Wt=ma Wt=mg g=9.8m/s² Fg=G m1m2/d²

13. Work • Work – transfer or conversion of energy • Energy has six forms and two states • Kinetic energy – energy of motion KE=1/2mv² kg m²/s² Nm joule • Potential energy – stored energy PE=mgh kg m/s² m Nm joule • Conservation of energy – energy can be converted to another form

14. Power • Power – rate at which work is done or converted to another form • P=W/t =Fd/t =F/v kgm²/s²/s or J/s Watts hp=746W • Simple Machines multiply force or distance W=Fd make work easier • Levers – bar, wheel-axel and pulley • Inclined Planes – ramp, wedges and screws • MA = Le/Lr or Fr/Fe Eff = Wo/Wi

15. Momentum • Momentum – property or tendency of a moving object • p=mv kg m/s • Vector – magnitude and direction • Impulse – change in momentum • Requires an unbalanced force • Ft = Δp = mv f – mv i

16. Heat • Heat – thermal energy that moves • Thermal Energy – causes particle vibration or sum of internal energies • KE increases and volume will increase…………thermal expansion • Measured in Joules or cals 1c=4.1J BTU • Temperature measures KE of atoms • K °C °F • Tf=(9/5Tc)+32 Tc=5/9(Tf-32) K=C+273

17. Heat is transferred by Conduction, Convection and Radiation • Heat transfer can cause a Phase Change S-L-G as heat is gained • Heating Curves plot Q vs T where the Heat of fusion S-L and Heat of Vaporization L-G need to be added for a phase change • Heat gained or lost is calculated by Q=m Δt Cp Cp is specific heat • Cp low in metals high for water 4.184J/g°C wow that is high • measured on a calorimeter • Insulators vs Conductors

18. Electricity • Electricity – flow of electrons from pos to neg • Form of energy that can do work • Circuit is the path for electrons open – no flow closed – current • Circuits have conductors (wires), source (battery), switch, and loads • Current – number electrons flowing or the amount of energy I amps • Voltage – electrical potential energy or energy on each electron push on electrons V volts • Resistance – opposes flow loads R ohms

19. Ohm’s Law – V = I R • Resistors control the flow of electrons fixed or variable dimmer • Electric Charge – Proton=pos electron=neg opposites attract because fields ‘fit into’ one another • Static – charge by friction and the induction method lightning • Circuits are series and parallel • Series – all loads are on one path • Parallel – alternate path household • Short Circuit – path of least resistance

20. Electric Power – rate at which electric energy is converted to other forms • P=W/t watts 1W=1J/s • P=I V watts kiloWatts • Electric Energy – power x time kWh • Cost = EE x cost/kWh • Direct current (one direction) and Alternating Current (60 Hz) • Adapters convert AC to DC

21. Magnetism • Magnetism – field force due to the spin of electrons in an aligned magnetic domains in permanent mag • Electrons flowing also creates a mag field around the wire Right Hand Rule • Lining up domains creates poles North and South can’t be isolated • Electromagnet – temporary magnet has an iron core and wire carrying current and converts electric to mechanical energy • Electric Motors – electromagnet within a permanent magnet electric to mechanical • Generators – electromagnet in a permanent magnet mechanical to electrical • Transformers step up or step down voltage to save power

22. Waves • Wave – repeating disturbance that transfers energy in matter or space • Mechanical waves transfer energy through matter (the medium) and can be longitudinal or transverse • Electromagnetic waves are disturbances in electric and magnetic fields transverse • Longitudinal waves are a series of compressions and rarefactions ex: sound or seismic waves • Transverse waves are disturbances that are at right angles to transfer of energy • Crest Trough Nodes • Wavelength – distance from crest to crest

23. Amplitude – wave height Energy • Frequency – number of wavelengths or cycles per second 1/s Hz • Wave Speed=wavelength x frequency v = λ f m/s • Properties include: reflection, refraction, diffraction and interference • Reflection – change in direction from a surface θi = θr mirrors • Refraction – bending rays due to change in speed from one medium to another slowed bends toward normal • Diffraction – waves bend around a barrier

24. Interference – waves combine to produce another wave • Constructive – crests and troughs match and increase amplitude • Destructive – partial or complete cancellation • Standing – two waves equal in amplitude and wavelength from opposite directions appear not to move • Resonance – natural frequency an object vibrates when absorbs energy

25. Sound • Sound is a longitudinal wave caused by a vibration • Speed of sound depends upon the temperature and density of the medium s=λf • increase density increase speed • Increase temperature increase speed • Intensity is the energy amplitude • Loudness is how we perceive intensity decreases with distance measured in decibels-15dB whisper -150 • Pitch is how we perceive frequency below 20 Hz infra above 20,000 Hz ultra

26. Uses of sound include: echolocation, sonar, ultrasonic imaging and music • Doppler Effect – apparent change in pitch due to change in relative position of observer or source • ex: sirens and Corvetts red shifts

27. Light • Light is a transverse wave or a disturbance in electric and magnetic fields electromagnetic • Produced by an oscillating electron • c = 300,000,000 m/s in the vacuum of space • Duel nature – photons act as particles (photoelectric effect) and as waves (reflection,refraction,diffraction) • Range of frequencies of the electromagnetic spectrum radio-micro-IR-visible-UV-Xrays-gamma • Colors are λ of light ROYGBIV

28. Light is produced by incandescent, fluorescent, neon and by lasers • Polarized – block one plane of light • Lasers are used to produce Holograms • Optical Fibers – total internal reflection • Reflection by mirrors concave and convex • Refraction by lenses convex and concave • Images can br virtual or real, upright or inverted, magnified or reduced

29. GHSGT • Wednesday • Study!!!