Science- Earth knowledge organiser

• What is the atmosphere?

  The air around us made of gases
• What happens when the Sun heats the Earth's surface?

  Some radiation is absorbed, some reflected
• Why is the atmosphere important for Earth's temperature?

  It keeps Earth warmer than without it
• What are greenhouse gases?

  Gases that absorb and trap radiation
• Name two commonly known greenhouse gases.

  Carbon dioxide and methane
• What percentage of the atmosphere is oxygen?

  21%
• What percentage of the atmosphere is nitrogen?

  79%
• What is an ore?

  A rock from which a metal can be extracted
• What happens when metals are extracted from their ores?

  They undergo a series of processes for use
• Why might extraction of a metal not be economical?

  If the metal is found in low concentrations
• Why are carbon-based compounds considered greenhouse gases?

  They contain carbon and hydrogen
• What is expected if greenhouse gases in the atmosphere increase?

  Global warming can be expected
• What is global warming?

  • Gradual increase in Earth's temperature
  • Closely linked to rising carbon dioxide levels
• What is the carbon cycle?

  • Processes transferring carbon to different stores
  • Carbon released through combustion and respiration
  • Reabsorbed by plants during photosynthesis
• How is carbon released into the atmosphere?

  Through combustion of fossil fuels and respiration
• What are long-term changes to weather patterns called?

  Climate change
• What can climate change cause?

  Melting ice caps and rising sea levels
• What do scientists believe about human activity and climate change?

  It is a very likely cause of climate change
• What are metals considered in terms of natural resources?

  Metals are a natural resource found in compounds
• What are naturally occurring metals and their compounds called?

  Minerals
• What is an ore?

  An ore is a rock containing valuable minerals
• What does the extraction of metals involve?

  Separating metals from minerals and chemical reactions
• What happens to metals during extraction from ores?

  They undergo a chemical reaction to separate
• How can metals below carbon in the reactivity series be extracted?

  By reacting them with carbon in a displacement reaction
• What is the general reaction for extracting metals with carbon?

  carbon + metal oxide → metal + carbon dioxide
• How can metals above carbon in the reactivity series be extracted?

  By using electrolysis to separate them
• What are the disadvantages of recycling?

  • Separating rubbish can be a nuisance
  • Collection lorries produce pollution
  • Some materials are harder to recycle
• What gases formed the Earth's early atmosphere?

  Gases from volcanic activity
• What was the composition of the early atmosphere similar to?

  Similar to Mars and Venus today
• What gas was primarily present in the early atmosphere?

  Carbon monoxide (CO)
• What gases did volcanoes produce that contributed to the atmosphere?

  Nitrogen, methane (CH₄), and ammonia (NH₃)
• What were the main components of the Earth's early atmosphere?

  • Little or no oxygen
  • Large amounts of carbon dioxide
  • Water vapour
  • Small amounts of other gases
• How did water vapour contribute to the formation of oceans?

  It condensed to form liquid water
• What happens to carbon dioxide when oceans form?

  It dissolves in water and forms sediments
• How did primitive plants affect atmospheric oxygen levels?

  They produced oxygen through photosynthesis
• How did the percentage of oxygen in the atmosphere change over time?

  It gradually increased to support animal life
• What is the greenhouse effect?

  • Gases absorb heat radiated from Earth
  • Energy is released, keeping Earth warm
  • Involves gases like CO₂, CH₄, and water vapour
• How does the Earth's atmosphere interact with solar radiation?

  It allows sunlight to pass and absorbs infrared radiation
• What happens to infrared radiation emitted by the Earth?

  It is absorbed by greenhouse gases
• What evidence supports human activity causing climate change?

  • Correlation between CO₂ levels and fossil fuel consumption
  • Temperature changes linked to human activities
  • Measurement location and historical accuracy uncertainties