Science exam reveiw

• Rotation


  Spinning on its own axis
• Revolution


  Spinning around another object
• Formation of a star

  1. Birth: cloud of gas and dust collapses forming nebula → protostar

  2. Main life: nuclear fusion

  3. Death: runs out of hydrogen → red giant → white giant
• The Sun is 73% hydrogen and 25% helium
• Layers of the Sun

  • Core
  • Radiative zone
  • Convective zone
  • Chromosphere
  • Corona
• 4 main parts of the Sun

  • Sunspots
  • Prominences
  • Solar flares
  • Coronal mass ejections
• HR diagram


  • x= temperature y= luminosity
  • hot= blue cold= red
• Types of galaxies


  • Spiral
  • Barred spiral
  • Elliptical
  • Irregular
• Structure of the Milky Way

  • Nucleus
  • Central bulge
  • Disk
  • Spiral arms
  • Spherical component
  • Halo
• Spectral analysis


  Motions of celestial objects by examining light emission or absorption
• Doppler effect


  • Redshift= moving away
  • Blueshift= getting closer
• Retrograde motion


  Move in one direction, sometimes planets appear to be moving backwards because earth is in a faster orbit so it passes slower planets
• Geocentric model claimed earth was the center of the universe (did not explain retrograde motion)
• Heliocentric model claimed the sun was the center of the universe which explained retrograde motion
• Black holes


  Each galaxy has a black hole at the center. black holes have gravity so strong not even light can escape. When galaxies collide the black holes move towards each other and eventually merge.
• Moon phases


  • New moon
  • Waxing crescent
  • First quarter waxing gibbous
  • Full moon
  • Waning gibbous
  • Last quarter
  • Waning crescent
• Impact of the Moon on Earth

  • Tides
  • Stabilize tilt
  • Length of day
  • Cultural and biological
• Solstices and equinoxes


  • Summer solstice: june 21st/ longest day of the year
  • Winter solstice: december 21st/ shortest day of the year
  • Spring equinox: march 21st/ equal length day and night
  • Fall equinox: september 21st/ equal length day and night
• Solar eclipse


  Occurs when the Moon passes between the Sun and Earth, causing the Moon to cast a shadow on Earth.
• Lunar eclipse


  Occurs when Earth is between the Sun and the Moon, causing Earth to cast a shadow on the Moon.
• Law of electric charge

  • Like charges repel
  • Opposite charges attract
• Ways to transfer static electricity

  • Charging by contact: touching charged objects
  • Charging by induction: not touching but holding close
  • Charging by friction: rubbing objects together
• Insulators


  Resist the flow of electrons (rubber, glass)
• Conductors


  Let electrons flow freely (copper, gold)
• Circuit symbols


  • Various circuit symbols
• Series circuits


  • Arranged one after the other
  • One path electrons flow
  • If path is interrupted circuit will not work
  • Current = same throughout
• Parallel circuits


  • Arranged so electrons flow along more than one path
  • Break in one path = others still function
  • Current flows through path with least resistance
• Formulas for series and parallel circuits

  • Series circuits: Current, Voltage, Resistance
  • Parallel circuits: Current, Voltage, Resistance
• Voltmeter


  Used to measure the electric potential difference (voltage) between two points in a circuit
• Ammeter


  Used to measure the electric current flowing through a circuit
• Percent efficiency


  Measure of how well a system converts input energy or resources into useful output
• Renewable resources


  • Solar Energy
  • Wind Energy
  • Hydropower
  • Biomass
  • Geothermal Energy
• Nonrenewable resources


  • Fossil Fuels
  • Nuclear Energy
• Ways to reduce energy consumption

  • Turning off the lights when leaving a room
  • Use LED lights
  • Switching to efficient appliances
  • Unplug devices
  • Lessen water usage
  • Keep the thermostat at a lower temperature
• Types of matter


  • Mixtures: Homogeneous, Heterogeneous
  • Pure substances: Elements, Compounds
• Particle theory


  • All matter is made up of particles
  • There are spaces between particles
  • Particles attract each other
  • Particles are always moving
• Physical properties


  • Color
  • Density
  • Melting Point
  • Boiling Point
  • Solubility
  • Conductivity
  • Malleability
  • Ductility
  • Hardness
  • Odor
• Chemical properties


  • Flammability
  • Reactivity
  • Corrosiveness
  • Toxicity
  • Acidity/Basicity (pH)
  • Oxidation/Reduction (Redox) Potential
  • Stability
  • Hygroscopicity
• Physical change


  • Change in state (solid liquid gas)
  • Change in shape/size
  • Change in appearance
  • No new substance is created, chemical composition remains the same
• Chemical change


  • Color change
  • Release of gas
  • Change of chemical composition
  • Chemical reaction occurs and is irreversible