Earth's Changing Atmosphere Through Time
Year 9 Science Understanding atmospheric evolution Cross-curricular Biology, Chemistry & Physics
WALT - We Are Learning To
Describe how Earth's atmosphere has changed over geological time Explain biological, chemical, and physical processes behind atmospheric changes Investigate the impact of human activities on modern atmospheric composition Understand how these changes affect life and Earth's temperature balance
Success Criteria
I can explain key stages in atmospheric development I can describe processes like photosynthesis and volcanic activity affecting gases I can carry out practical investigations on gas composition I can relate atmospheric changes to climate and life on Earth I can discuss and present scientific ideas confidently
Starter Activity: Think-Pair-Share
What is the atmosphere made of today? How do you think Earth's atmosphere started? Discuss in pairs for 3 minutes Share your ideas with the class
Earth's Atmospheric Timeline
Early vs Modern Atmosphere
{"left":"Early Earth: Carbon dioxide, water vapor, methane, ammonia, no oxygen","right":"Modern Earth: 78% nitrogen, 21% oxygen, 1% other gases including CO2"}
The Great Oxidation Event
2.4 billion years ago - game changer! Cyanobacteria began photosynthesis Oxygen was toxic to early life forms Mass extinction of anaerobic organisms Paved the way for complex life
Practical Investigation: Oxygen and Carbon Dioxide Changes
Work in groups of 4-5 with assigned roles Jar A: Candle alone Jar B: Candle with fresh leaf Jar C: Control (no candle, no leaf) Time how long candles burn Discuss what gases are used and produced
Investigation Question
Why does the candle in Jar B (with the leaf) burn longer than the candle in Jar A?
Cross-Curricular Connections
Biology: Photosynthesis increases oxygen, affects carbon cycle Chemistry: Gas composition changes, chemical reactions in atmosphere Physics: Greenhouse gases trap thermal energy, affect Earth's temperature All three work together to explain atmospheric evolution!
Human Impact on Modern Atmosphere
Industrial Revolution: massive fossil fuel burning Deforestation reduces oxygen production CO2 levels rising rapidly Greenhouse effect intensifying Climate change accelerating
Plenary: Quick Quiz & Reflection
Quiz: Test your knowledge of atmospheric changes Reflection: How do living organisms affect the atmosphere? One-minute paper: Write one thing you learned and one question you still have