Question

What does the Earth's atmosphere consist of? Why would you die of suffocation if you were to parachute from an airplane at an elevation of \(12 \mathrm{~km} ?\) (B)

Short answer

The Earth's atmosphere consists of nitrogen (approx. 78%), oxygen (approx. 21%), argon (approx. 0.93%), carbon dioxide (approx. 0.041%), water vapor (0-4%), and trace amounts of other gases. At an elevation of \(12 \mathrm{~km}\), atmospheric pressure and oxygen levels are significantly lower than at sea level. Due to this lack of oxygen, a person parachuting from \(12 \mathrm{~km}\) would experience hypoxia, with symptoms like shortness of breath, impaired thinking, and unconsciousness, eventually leading to death. To avoid these life-threatening conditions, they would need supplemental oxygen or to descend to a lower altitude quickly.

Step-by-step solution

Introduction to Earth's Atmosphere

The Earth's atmosphere consists of a mixture of gases, including nitrogen, oxygen, carbon dioxide, water vapor, and trace amounts of other gases. As altitude increases, the atmospheric pressure and oxygen levels decrease. This is important because it impacts the body's ability to perform tasks and can lead to dangerous situations at high altitudes.

Composition of Earth's Atmosphere

The major components of the Earth's atmosphere are: - Nitrogen (N2) - approx. 78% - Oxygen (O2) - approx. 21% - Argon (Ar) - approx. 0.93% - Carbon dioxide (CO2) - approx. 0.041% - Water vapor (H2O) - variable, approximately 0-4% - Trace amounts of other gases These proportions remain fairly constant at lower altitudes but vary with height.

Atmospheric Pressure and Oxygen Levels

The Earth's atmospheric pressure and oxygen levels are influenced by elevation. As the elevation increases, atmospheric pressure and oxygen levels decrease. At an altitude of \(12 \mathrm{~km}\), the atmospheric pressure is significantly lower than at sea level. The partial pressure of oxygen (a measure of oxygen in the air) is also reduced, meaning there is less oxygen available for us to breathe.

The Effects of Low Oxygen and High Altitude on the Body

Oxygen, which we breathe in from the air, is essential for our body to function properly. When there is not enough oxygen available, such as at high altitudes, it can cause a condition called hypoxia. Symptoms of hypoxia include shortness of breath, impaired thinking, and unconsciousness, and it can eventually lead to death if the person does not receive extra oxygen or return to a lower altitude. At an altitude of \(12 \mathrm{~km}\), there is not enough oxygen in the air for a person to survive without supplemental oxygen, like the oxygen provided by an oxygen mask in an airplane.

Suffocation at an Elevation of \(12 \mathrm{~km}\)

When parachuting from an airplane at \(12 \mathrm{~km}\) elevation, a person would likely die of suffocation due to the lack of oxygen in the air. The individual would experience the symptoms of hypoxia, including impaired thinking, unconsciousness, and eventually death as their body cannot function without enough oxygen. They would need supplemental oxygen or to descend to a lower altitude quickly to avoid these life-threatening conditions.

Key concepts

Atmospheric Pressure

Understanding atmospheric pressure is crucial when studying the composition of Earth's atmosphere. Atmospheric pressure is the weight of the air above us, and it decreases significantly as you climb higher above sea level.

This decrease in pressure can be exemplified by imagining a stack of air molecules. Near the surface of the Earth, the stack is taller, meaning there are more molecules above you, which translates into higher pressure. As altitude increases, this stack becomes shorter, leading to lower pressure. This is why activities that lead to a rapid increase in altitude, such as parachuting from an airplane at an elevation of 12 km, can be dangerous without proper equipment, due to the low atmospheric pressure.

Oxygen Levels

Oxygen is a vital component of the air we breathe, and its levels in the Earth's atmosphere are of particular importance to all living organisms. While approximately 21% of the atmosphere is composed of oxygen at sea level, this percentage remains constant but the actual density of oxygen molecules decreases with altitude.

This is because the atmospheric pressure drops, and with fewer oxygen molecules in a given volume of air, our lungs absorb less oxygen with each breath. At high altitudes, such as 12 km, the scarcity of oxygen can have severe effects on the body, which are exacerbated by the low pressure. Hence, supplemental oxygen is a necessity in these environments to maintain normal physiological functions.

Hypoxia

Hypoxia refers to a deficiency in the amount of oxygen reaching the body's tissues. It's a risk for anyone at high altitudes, where oxygen levels are low due to decreased atmospheric pressure.

There are several symptoms associated with hypoxia, ranging from breathlessness and headaches to impaired judgment and even unconsciousness. This condition can occur rapidly, and without immediate intervention, such as the administration of supplemental oxygen or descent to lower altitude, hypoxia can lead to life-threatening complications and death. It's critical for those engaging in high altitude activities to be aware of the signs of hypoxia and to have appropriate safety measures in place.

High Altitude Effects

The effects of high altitude on the human body are complex and can be dangerous if unprepared. Due to the lower atmospheric pressure and reduced oxygen levels, individuals can experience not only hypoxia but also other issues such as altitude sickness.

Common symptoms include dizziness, fatigue, nausea, and difficulty sleeping. Long-term exposure without proper acclimatization can lead to serious health problems like high altitude cerebral or pulmonary edema. For someone parachuting from 12 km, the effects of high altitude hit rapidly and can lead to unconsciousness within minutes, emphasizing the need for an oxygen support system in such extreme conditions.