topic test

• earth is divided into three sections: lithosphere, atmosphere, and hydrosphere
• the lithosphere is the crust of the earth consisting of rocks, minerals and crystals
• the atmosphere is the whole mass of gases surrounding the earth
• the hydrosphere is the total amount of water on the planet (including water in the air, on the surface and underground)
• biosphere is the part of the earth that is inhabited by living things
• the earth insides are divided into four parts

  the crust, mantle, inner core and outer core
• earth's crust is formed as molten magma cools and solidifies
• the mantle is a hot, semi-molten layer beneath the crust
• minerals are solids made up of atoms of elements; naturally occurring compounds
• rocks are a collection of different types of minerals
• native elements contain one type of atom
• compounds have different types of atoms
• atoms in minerals are arranged as a crystal lattice.
• atoms are the basic building blocks of matter
• how do crystals form?

  molten rock cools and atoms bond together into mineral crystals OR water that has atoms of dissolved elements in it, evaporates (may get very close to each other and bond to form solid minerals)
• if cooling is slow, big crystals grow; vice versa
• what are the properties of minerals?

  shape, colour, lustre, streak, hardness, form and cleavage
• shape is the natural configuration taken by the mineral as the crystal forms
• lustre is how the light reflects (non-metallic, metallic)
• streak is the colour of a mineral in a finely powdered for; can be found by scratching mineral against an unglazed tile.
• hardness is the measure of the mineral's surface resistance to abrasion; moh's scale
• form is the general shape of the mineral (single crystal, a group or a dense mass)
• cleavage is the tendency of a mineral to break in certain preferred directions along a smooth surface
• fracture is the way a mineral naturally breaks other than along a flat, cleavage plane
• striations are narrow lines that cross certain minerals surfaces
• moh's scale measures hardness of a mineral and its based on what can and cannot be scratched
• igneous rocks are formed from the cooling and solidification of magma or lava
• what are the two types of of igneous rocks?

  extrusive and intrusive
• extrusive rocks are formed at or near the surface of the earth from lava
• intrusive rocks are formed underground from magma
• because extrusive rocks cool quicker, they have little to no crystals
• because intrusive rocks have a longer period of time to cool, they have many more, larger crystals
• features of igneous rocks include...

  • they have crystals
  • the crystals are usually randomly orientated
  • crystals can be different sizes
  • no layers
  • are dense and hard
  • may have glassy appearance
  • may be porous (vesicular)
• a sedimentary rocks is a rock formed from the compaction and cementation of sediments
• sediments are fragments of rocks that have been broken down as a result of weathering
• features of sedimentary rocks include...

  • pieces of smaller rocks and/or sediments
  • often contain fossils
  • layers of different colours
  • soft and crumbly
  • grains made up of sand, silt or gravel
• metamorphic rocks are formed from the transformation of other rocks through heat and pressure without completely melting
• a parent rock is the original rock that changed into a metamorphic rock
• features of metamorphic rocks include...

  • have layers made up of crystals which are the same size
  • crystals are long and run parallel to each other
  • may also be glassy in appearance but more of an opaque black colour
  • hard but not as hard as igneous rocks
• earth's age is 4.5 billion years old