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Mobile App Chapter 24: Problem 29
The second law of thermodynamics says that the entropy (a measure of disorder) of the universe is always increasing. Yet complex living organisms exist. Why does this not violate the second law of thermodynamics?
Short Answer
Expert verified
Living organisms decrease their internal entropy by consuming energy, which increases the environment's entropy, aligning with the second law of thermodynamics.
Step by step solution
01
Understand the Second Law of Thermodynamics
The second law of thermodynamics states that the total entropy of an isolated system can never decrease over time. Entropy is a measure of disorder or randomness in a system.
02
Define Entropy in Context of the Universe
In the context of the universe, entropy tends to increase over time. Even though local decreases in entropy can occur, such as in the formation of complex structures, the overall entropy of the universe still increases.
03
Explain Local Decreases in Entropy
Living organisms can locally decrease entropy by creating order in their cells and structures. However, this process requires energy, typically from the environment or food.
04
Relate to the Environment
The energy taken in by living organisms comes from their surroundings, leading to an increase in the entropy of the environment. Thus, the total entropy of the universe still increases.
05
Conclusion on Entropy and Life
The apparent decrease in entropy in living organisms does not violate the second law because the increase in order (decrease in entropy) within organisms is more than compensated by the increase in entropy in the environment, maintaining overall entropy increase in the universe.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
entropy
Entropy is a fundamental concept in understanding the second law of thermodynamics. It serves as a measure of disorder or randomness in a system. When we say a system's entropy increases, we mean its particles are becoming more disordered.
For instance, when ice melts into water, the structured arrangement of molecules in ice becomes disordered in liquid water, from lower to higher entropy.
Entropy tends to increase naturally over time as systems move towards equilibrium, a state where energy is evenly distributed. Understanding entropy helps us grasp why processes occur in a certain direction and why energy transformations aren't 100% efficient.
For instance, when ice melts into water, the structured arrangement of molecules in ice becomes disordered in liquid water, from lower to higher entropy.
Entropy tends to increase naturally over time as systems move towards equilibrium, a state where energy is evenly distributed. Understanding entropy helps us grasp why processes occur in a certain direction and why energy transformations aren't 100% efficient.
isolated system
An isolated system is a system that doesn't exchange energy or matter with its surroundings. Think of it as a sealed, perfectly insulated container. The second law of thermodynamics specifically applies to isolated systems, stating that their total entropy can never decrease over time.
In real-world physics, perfectly isolated systems don't exist, but this concept helps in understanding theoretical foundations.
In real-world physics, perfectly isolated systems don't exist, but this concept helps in understanding theoretical foundations.
- In an isolated system like a closed universe, any process occurring within it must result in an increase in total entropy.
- This implies that even if some parts of the system become more ordered, the overall disorder must increase.
living organisms
Living organisms are a fascinating exception to the rule of increasing entropy. They appear to decrease entropy locally by forming highly ordered structures like cells and tissues. But this doesn't violate the second law of thermodynamics. Why?
It's because organisms use energy from their surroundings (food, sunlight) to build and maintain order.
It's because organisms use energy from their surroundings (food, sunlight) to build and maintain order.
- This energy intake leads to an increase in entropy in the environment that compensates for the local decrease within the organism.
- Thus, while the organism's entropy decreases, the total entropy, including the environment, still increases.
energy transfer
Energy transfer plays a vital role in maintaining order within living organisms. Energy must be transferred from the environment to build complex biological structures. This process involves moving energy from one place to another, such as consuming food or absorbing sunlight.
During energy transfer, there's always some energy that becomes unavailable for work, increasing the overall entropy of the environment.
Thus, the more energy an organism consumes to sustain order, the greater the compensation in entropy elsewhere, ensuring the second law of thermodynamics remains respected.
During energy transfer, there's always some energy that becomes unavailable for work, increasing the overall entropy of the environment.
- For example, when an organism eats, it converts food into usable energy, but also produces heat, a less ordered form of energy.
Thus, the more energy an organism consumes to sustain order, the greater the compensation in entropy elsewhere, ensuring the second law of thermodynamics remains respected.
universe entropy
The universe's entropy is always increasing as dictated by the second law of thermodynamics. Even though parts of the universe may experience decreases in entropy, like the formation of stars or the growth of life, the grand total always trends upward.
This broad increase is crucial because it drives the direction of all natural processes.
This broad increase is crucial because it drives the direction of all natural processes.
- When looking at isolated systems or even vast sections of the universe, it's clear that processes naturally head towards higher disorder.
- This universal behavior explains why energy transformations are never 100% efficient—there's always some entropy generated.
