Question 1: Define the term 'early atmosphere' and describe its main components during Earth's formative years.

Answer: The early atmosphere refers to the Earth's initial gaseous envelope, mainly composed of nitrogen, carbon dioxide, water vapour, and trace gases, before the development of a stable oxygen-rich atmosphere.

Question 2: Explain how volcanic activity contributed to the composition of the early atmosphere.

Answer: Volcanoes released gases such as carbon dioxide, sulphur dioxide, and water vapour, which accumulated to form the primordial atmosphere.

Question 3: What is the significance of water vapour in the early atmosphere?

Answer: Water vapour condensed to form oceans, which played a key role in supporting life and further atmospheric changes.

Question 1: Calculate the volume of carbon dioxide (CO₂) in cubic metres in a 1000 km³ volume of the early atmosphere, if CO₂ made up 80% of the gases. (Use 1 km³ = 10^9 m³)

Answer: 8 x 10^11 m³

Question 2: If the current atmosphere contains approximately 21% oxygen, estimate the change in oxygen volume in cubic metres if 100 km³ of Earth's atmosphere originally contained no oxygen. Assume the atmosphere's total volume is 1,000 km³.

Answer: 210 x 10^9 m³

Question 1: Design a simple experiment to test the effect of volcanic gases on the composition of an atmospheric sample. Include variables to control and safety precautions.

Answer: Students could simulate volcanic gases by releasing controlled amounts of CO₂ and SO₂ into a sealed container with a sample of air, then analyse changes in gas composition using appropriate sensors or chemical tests. Variables to control include gas amounts, temperature, and pressure. Safety precautions involve using protective equipment and working in a well-ventilated area to handle toxic gases.

Question 1: A team of scientists measures that a sample of ancient rock contains sulphur compounds indicative of volcanic activity. Explain what this suggests about the composition of Earth's early atmosphere and its formation process.

Answer: It suggests that volcanic activity released sulphur gases, which contributed to the atmospheric composition. This supports the idea that Earth's early atmosphere was formed mainly through volcanic outgassing.

Question 1: Describe the process by which oxygen levels increased in Earth's atmosphere and explain its significance for the development of life.

Answer: Oxygen levels increased through photosynthesis by early algae and plants, which converted carbon dioxide and water into oxygen. This gradual increase led to the formation of an oxygen-rich atmosphere, enabling the evolution of aerobic organisms and complex life forms.

Question 2: Multiple Choice: Which gas was the primary component of Earth's early atmosphere?

Answer:

Question 1: Discuss how knowledge of atmospheric gases and their effects can aid in the development of sustainable technologies or climate change mitigation.

Answer: Understanding the composition and effects of atmospheric gases helps develop cleaner energy sources, such as carbon capture and storage, and informs policies to reduce greenhouse gas emissions, aiding in climate change mitigation and promoting sustainability.