Science 8

• Newton's Laws of Motion


  • Law of inertia
  • Law of acceleration
  • Law of Interaction
• Law of inertia


  States that an object at rest will remain at rest unless acted upon by a net force
• Force


  A push or pull that causes change in the motion of an object
• Types of Force


  • Contact forces - two or more surface touch and interact
  • Non-Contact force - present in nature
• Motion


  Caused by unbalanced forces
• Speed


  Length of distance traveled by a certain amount of time
• Velocity


  Change of displacement
• Acceleration


  Change of velocity
• Gravity = 9.8 m/s²
• Work


  Change in energy
• Work done


  • By an object - Loses energy
  • On an object - Gains energy
• Unit of Force


  kg m/s² or N
• Unit of work


  Unit of Force x unit of displacement = Nm or (J)
• Potential energy


  Stored energy /Energy ready to be released
• Formula for Potential Energy


  PEg = mgh (Mass x gravity height)
• James Prescott Joule - 1 Newton meter
• Energy


  Ability to do work
• Kinetic energy


  The energy passed by bodies in motion (Energy in motion)
• Formula for Kinetic Energy

  KE = 1/2mv² (1/2 x mass x velocity)
• Sound waves can move through matter
• Factors that affect the speed of sound as it travels through a medium


  • Density of a Medium - Sound waves move well through dense materials
  • Elasticity of a medium - Sound waves travel fast through elastic materials
  • Temperature of air - sound waves travel faster through warm air than cold air
• Prism


  A triangular piece of thick glass
• White light is made up of different colors
• Index of refraction


  Common indicator of the optical density of a material
• Dispersion


  Process of which light is separated into its colors
• Diffraction


  Phenomenon of light waves capable of bending around obstacles
• Diffraction Grating


  Device used to study diffraction
• Retina


  Contains cells that are sensitive to colors
• Rods


  Enable you to see in black and white
• Cones


  Provide you with color vision in bright light
• Layers of the Earth


  • Crust - outer most layer of the earth
  • Mantle - dense layer of hot semi solid and solid rock
  • Core - Third layer of the earth
• Continental crust


  35 to 70 km thick
• Oceanic Crust


  5 to 10 km thick
• Lithosphere


  Solid rocky sphere
• Tectonic plates


  The lithosphere broken into pieces
• Parts of the Core

  • Outer core - a liquid layer with 2200 km thickness
  • Inner core - a solid liquid with 1250 km thickness
• Newton's Laws of Motion


  • Law of inertia
  • Law of acceleration
  • Law of Interaction
• Types of Faults


  • Active faults - where displacement of plates usually occurs
  • Inactive faults - where earthquakes are usually less
• Law of inertia


  States that an object at rest will remain at rest unless acted upon by a net force
• Fault plane


  Fault movement takes place