No sublimation for human body in vacuum? [Thermodynamics]

In summary, in Thermodynamics, we learn about the saturation pressure and temperature of substances, specifically water. Water boils at 100 degrees Celsius at atmospheric pressure, but altering the pressure changes the energy needed for boiling. The enthalpy of vaporization decreases with increasing pressure. In a space environment, only the fluids in the human body evaporate, while the body itself remains solid, similar to how a spacecraft hull does not evaporate.
  • #1
Satonam
38
1
In my Thermodynamics course, we recently learned about the saturation pressure and saturation temperature of different substances -mainly water. As you know, the saturation temperature at which a substance begins to boil is specific to a fixed saturation pressure. Water only boils at 100 centigrade while at atmospheric pressure; increasing that pressure in a P-v diagram raises the energy required to start boiling water, while decreasing that pressure reduces it. (Albeit, the enthalpy of vaporization decreases with increasing pressure)

Why is it that only the fluids in the body evaporate, accounting for the swelling, while the human body itself remains solid whilst exposed to the vacuum temperature in a space environment?
 
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  • #2
Same reason the spacecraft hull doesn't evaporate.
 

1. What is sublimation and how does it relate to thermodynamics?

Sublimation is the process by which a substance transitions directly from a solid to a gas without passing through a liquid state. In thermodynamics, sublimation is a phase change that involves a transfer of energy, typically from heat, which causes the solid molecules to vibrate and escape into the gas phase.

2. Can sublimation occur in a vacuum?

Yes, sublimation can occur in a vacuum. In fact, sublimation is more likely to occur in a vacuum because there is no atmospheric pressure to keep the solid molecules in their condensed state.

3. Why is sublimation not possible for the human body in a vacuum?

Sublimation requires a significant amount of energy, typically in the form of heat, to overcome the strong molecular bonds in a solid. The human body does not have enough internal heat to undergo sublimation, even in a vacuum.

4. What happens to a human body in a vacuum instead of sublimation?

In a vacuum, a human body would undergo a different process known as desiccation. Desiccation is the process by which a body loses moisture due to the low pressure and lack of humidity in a vacuum. This process would cause the body to become mummified rather than undergo sublimation.

5. Are there any other factors that prevent sublimation of the human body in a vacuum?

Yes, in addition to the lack of internal heat, the human body is also composed of complex organic compounds that have a higher melting point than most other substances. This means that even if there was enough heat present, the body would not sublimate due to the strong molecular bonds within these compounds.

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