Science10

• Plate tectonics


  A theory that the Earth's outer shell is divided into several plates that glide over the mantle, the rocky inner layer above the core
• Types of plate boundaries

  • Divergent boundaries - Two plates moving apart/away from each other
  • Convergent boundaries - Two plates moving towards each other to form a subduction zone or continental collision
  • Transform boundaries - Two plates slide/grind past each other along transform faults
• Divergent boundaries


  • Also called constructive or extensional boundaries
• Transform boundaries


  • Also called conservative or strike-slip boundaries
• Sinistral motion


  Left side toward the observer
• Dextral motion


  Right side toward the observer
• Regions of the Earth's crust

  • Continental crust
  • Oceanic crust
• Continental crust


  • Mainly made up of silicon, oxygen, aluminum, calcium, sodium and potassium
  • Thickness is mostly 35-40km
  • Found under land masses
  • Made of less dense rocks like granite
• Oceanic crust


  • Around 7-10km thick, average 8km
  • Found under the ocean floor
  • Made of dense rocks like basalt
  • Heavier than continental crust
• Mantle


  Extends 2900km from the Earth's surface<|>Makes up about 80% of the Earth's total volume and 68% of its total mass<|>Solid, as P-waves and S-waves can pass through it<|>Mostly made of the elements silicon, oxygen, iron, and magnesium<|>Lower part has more iron than the upper part
• Layers of the Earth


  • Inner core
  • Outer core
  • Mantle
• Outer core


  • 2900km below the Earth's surface
  • 2250km thick
  • Made of iron and nickel
  • Temperature reaches up to 2000 degrees Celsius
• Inner core


  • Solid iron and nickel
  • Radius of 1300km
  • Temperature reaches 5000 degrees Celsius
• Earthquake


  A vibration of the Earth produced by the rapid release of energy, often due to slippage along a fault in the Earth's crust
• Seismic waves


  Waves that radiate in all directions from the focus of an earthquake in the form of body waves and surface waves
• Main types of seismic waves

  • Body waves (P-waves and S-waves)
  • Surface waves (Love waves and Rayleigh waves)
• P-waves

  Primary, longitudinal waves that can travel through solids, liquids, and gases.Travels parallel in its direction
• S-waves

  Secondary, waves that can only travel through solids.Travels perpendicular to its direction
• Love waves


  Surface waves that travel along the surface of the Earth above the lithosphere
• Rayleigh waves


  Surface waves that travel along the surface of the Earth, with a combination of longitudinal compression and dilation resulting in elliptical motion of points on the surface
• Surface waves are the most damaging type of seismic waves
• Surface waves spread out most in time, producing a long wave duration on seismographs
• The continental drift theory was proposed by Alfred Wegener in 1912 and had several lines of evidence supporting it
• The electromagnetic spectrum is a continuum of electromagnetic waves arranged by frequency and wavelength
• Gravity is a force that pulls everything towards the center of the Earth, discovered by Isaac Newton
• Mass


  Quantity representing the amount of matter in a particle or object, expressed in kg
• Friction


  A force between two bodies in contact that stops an object from sliding by acting in the opposite direction of the sliding movement
• Radio waves


  The longest wavelength and lowest frequency waves in the electromagnetic spectrum, produced by electricity oscillating in an aerial or antenna and used to transmit sound and picture information over long distances
• Microwaves


  Used in satellite communications and can penetrate the ionosphere
• Infrared waves


  Waves beyond the red end of the visible spectrum, too long to be visible to the naked eye, emitted by hot objects
• Visible light waves


  The only portion of the electromagnetic spectrum visible to the human eye
• Ultraviolet waves


  Invisible radiation beyond the violet end of the visible spectrum, with shorter wavelengths and higher energy than visible light
• X-rays

  Short wavelength, high frequency waves produced by the rapid acceleration of electrons colliding with atoms
• Gamma rays


  The highest energy waves in the electromagnetic spectrum, produced by nuclear reactions
• Paramagnetic substances


  Slightly attracted by strong magnets
• Ferromagnetic substances


  Strongly attracted to magnets, such as iron and steel
• Diamagnetic substances


  Slightly repelled by magnets, such as table salt, mercury, zinc, and gold
• Magnetite

  Substances that are already magnetized, also called "permanent magnets"
• Lodestones


  Natural magnets
• Magnetism, the natural force that causes magnets to function, became known to people many centuries ago