December 9, 2015
7 th grade Chapter 9.3-9.5

• Wanted to be a writer; twin sister a painter
• Friend died of cancer – decided to be a doctor instead
• Lost job in WWII Italy because she was Jewish
• Started working in her bedroom, then as a refugee
• Discovered how nerves grow
• Won 1986 Nobel Prize in medicine

• Rocks are usually mixtures of minerals and other components o Can be 1 mineral or several
• 4 main traits to classify rocks:
1. Mineral composition
2. Color
3. Texture
4. Origin

• 3 major groups for rocks
• Determine rock group based on other properties
Igneous rock: formed from cooling magma or lava
Sedimentary rock: forms when particles of other rocks, plants, or animal remains are pressed and cemented together
Metamorphic rock: when a rock is changed by heat, pressure, or chemical change, usually deep underground

• Formed from magma or lava, which is high in silica
• When it forms below the crust, it’s called intrusive
• Above the crust, extrusive
Trends (Not Always True):
• High in silica = dark rocks
• Low in silica = lighter-colored rocks
• When it cools quickly, it’s hard to form big crystals, so very fine grains in the texture.
• Hard, dense, and durable = good for arrowheads, countertops, fortresses

Sediment: small, solid particles of rocks or living things
• Sedimentary rocks form when sediment is deposited by water or wind and eventually stuck together
• Usually soft
• Sandstone and limestone are important building materials – sometimes used to make concrete too

Weathering
& Erosion
Deposition Compaction Cementation

Clastic rock: rock fragments are squeezed together.
Classified according to how big the particles are. E.g. conglomerate, shale, sandstone
Organic rock: formed when remains of plants or animals are pressed together. E.g. coal from swamp plants, limestone from shells & skeletons that are high in calcium
Chemical rock: usually formed from solutions. E.g.
Rock salt, limestone when it’s from evaporation

• Start off as sedimentary or igneous rocks, then are changed by heat, pressure, chemical changes, or a combo of these processes. E.g. marble, slate
• Appearance, texture, and crystal structure of the minerals changes
• Classified by pattern of the grains
• Used as building materials, old blackboard, etc.
• Most metamorphic rocks are foliated
Foliated: thin, flat layers in a rock