earth and atmosphere

• What is the outermost layer of the Earth called?

  Crust
• What is the process called that allows rocks to change forms over millions of years?

  Rock cycle
• What are rocks made of?

  Grains
• How does the texture of a rock depend on its grains?

  It depends on the size and shape of the grains
• What type of grains does sandstone have?

  Rounded grains
• Why is sandstone considered porous?

  Water can get into gaps between grains
• What type of grains does granite have?

  Interlocking grains
• Why are rocks with interlocking grains not porous?

  They do not have gaps between grains
• What happens to rocks during chemical weathering?

  Rainwater reacts with minerals in the rock
• What makes rainwater slightly acidic?

  Dissolved gases
• What occurs during physical weathering when rocks are heated and cooled?

  Minerals expand and contract, causing cracks
• What is freeze-thaw action?

  Water freezes in cracks, expanding them
• What is biological weathering?

  Rocks are broken by plants and animals
• How do plant roots contribute to weathering?

  They grow into cracks and enlarge them
• What is the term for the movement of weathered rock pieces?

  Erosion
• How are small rock fragments transported?

  By rivers
• What do we call small rock fragments?

  Grains
• What happens to grains when water slows down?

  Some grains are deposited
• How do sediments form layers?

  By deposition at the bottom of water bodies
• What happens to sediments when sea water evaporates?

  Salts are left behind
• What occurs to the bottom layers of sediment over time?

  They get compacted and cemented
• What is the process of forming sedimentary rock called?

  Cementation
• What can happen to trapped animals or plants in sediment?

  They may form fossils
• What can happen to buried plant material?

  It may turn into coal
• What is molten rock called?

  Magma
• What can happen to tiny sea plants and animals when buried?

  They may turn into oil or natural gas
• What is lava?

  Magma that flows out of volcanoes
• How are igneous rocks formed?

  When magma cools down and solidifies
• What type of igneous rocks form from lava?

  Extrusive rocks
• How do intrusive igneous rocks form?

  From magma that cools underground
• What can change sedimentary or igneous rocks into metamorphic rocks?

  High heat or high pressure

  
• What are the properties of different types of rocks?

  • Sedimentary:
  • Examples: limestone, shale, sandstone, chalk
  • Usually rounded grains
  • Often soft or crumbly
  • Often porous
  • Igneous:
  • Examples: basalt, granite, gabbro, obsidian
  • Crystals (interlocking grains)
  • Hard
  • Not usually porous
  • Metamorphic:
  • Examples: marble, quartzite, slate, gneiss
  • Crystals often in bands of different color
  • Hard
  • Not usually porous
• What is the rock cycle?

  A process linking rock formation and weathering

  
• What is the composition of the Earth's atmosphere?

  78% nitrogen, 21% oxygen, 1% other gases
• What gases are included in the 1% of other gases in the atmosphere?

  Water vapour, carbon dioxide, noble gases
• What has been happening to the level of carbon dioxide in the atmosphere?

  It has been increasing for many years
• What is the main cause of increased carbon dioxide levels?

  Human activity, especially burning fossil fuels
• What effect does carbon dioxide have on the atmosphere?

  It traps heat and causes climate change
• What are the expected long-term effects of climate change?

  Rising sea levels and extreme weather events
• What are countries trying to do about carbon dioxide emissions?

  Work together to reduce emissions