Chemistry

• Describe the process that led to the oceans forming

  The earth starting to cool and water vapour in the atmosphere condensed and fell as rain
• What produces gases that made up the atmosphere?

  Lots of volcanic activity produced nitrogen
• What do scientists think the early atmosphere was like?

  Like the atmosphere of venus or mars mainly carbon dioxide
• Why do we not know for certain what the earths atmosphere was like in the past?

  Evidence is limited as it happened 4.5 billion years ago
• What is the composition of the earths atmosphere today?

  80% nitrogen

  20% oxygen