The Evolution of the Atmosphere
This lesson covers the evolution of the Earth's atmosphere from its formation 4.6 billion years ago to the present day. It explores the role of volcanic activity, the formation of oceans, the emergence of photosynthetic life, and the reduction of carbon dioxide levels.
Learning objectives
- Describe the composition of the Earth's current atmosphere.
- Explain how the early atmosphere was formed and how it has changed over time.
- Describe how the levels of carbon dioxide and oxygen changed due to the evolution of plants and algae.
- Identify the processes that 'locked up' carbon in rocks and fossil fuels.
Lesson plan (60 minutes)
Starter · 5 min
Do Now: List the gases found in the air today and their approximate percentages.
Introduction · 15 min
Teacher-led explainer on the Early Atmosphere and the transition to the modern atmosphere using the provided script.
Main Activity · 25 min
Students work through differentiated worksheets (Support, Core, Stretch) based on their current attainment levels.
Review · 5 min
Self-assessment using the answer key provided by the teacher.
Plenary · 10 min
Plenary: 8-question multiple-choice quiz to check for understanding.
Key vocabulary
- Photosynthesis
- A process used by plants to make food using sunlight, taking in CO2 and releasing O2.
- Locked up carbon
- Carbon stored in rocks or fossil fuels for millions of years.
- Precipitates
- Solid bits that settle at the bottom of a liquid; often how CO2 was removed via oceans.
- Sedimentary Rock
- Rock formed from the accumulation of minerals or organic particles (e.g., limestone).
- Nitrogen
- A gas that makes up 78% of our atmosphere; it is very unreactive.
Core worksheet (first questions)
- 1. How many years ago was the Earth formed?
- 2. Besides CO2 and water vapour, name two other gases released by early volcanoes.
- 3. Give the balanced symbol equation for photosynthesis and explain how it changed the atmosphere.
- 4. Where is the 'locked up' carbon found today?
Quiz (sample)
1. What percentage of the Earth's atmosphere is currently Nitrogen?
- A. 21%
- B. 78%
- C. 0.04%
- D. 0.9%
2. Which of these provided the gases for the early atmosphere?
- A. Plants
- B. Volcanoes
- C. Oceans
- D. Comets
3. How were the oceans formed?
- A. Comets melted
- B. Water vapour condensed as the Earth cooled
- C. Plants released water
- D. Chemical reactions in the crust
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Support and Stretch worksheets, every answer and model answer, the teaching explainer and common misconceptions, editable and ready to print as PDF or Word.
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