There Are Four Laws Of Thermodynamics
Fact of the day: There are four laws of thermodynamics.
The laws of thermodynamics originated in the 1800s, when people were trying to improve the efficiency of heat driven engines, such as the steam engine.
(above) Steam engine
These laws are some of the most important laws, as they explain the behaviour of energy. The second law even explains, in some regards, the entire concept of time.
There were originally three laws of thermodynamics, but in the 1935, another law was proposed. This law was thought to be more fundamental than the other laws, so it became the zeroth law.
The Zeroth Law
This law states that if two objects are in equilibrium (they are balanced, and in this case with energy) even though they are in contact, there is no change of energy in either object. The net flow of energy between the objects is zero.
The First Law
The first law states that in a closed or isolated system, the total amount of energy in the system will remain unchanged. The energy can be transformed from one form to another, but the overall level will remain the same. Energy is always conserved. The universe is, as far as we know, a closed system, so the energy in the universe is always the same.
The Second Law
The Second law states that the entropy (amount of disorder) of an isolated system always increases over time. Lets say that you have an isolated plastic container, half with hot soup in it, half with cold ice cream in it (low entropy). This law says that the temperature of the soup gets colder, and the temperature of the ice cream will get warmer, therefore becoming equal (high entropy). This law explains why if you drop ink in water, it will not un-mix. Because of this, some people think this how time works. The universe (a closed system) will always have increasing total amount entropy. The possible fate of the universe, as all matter will have the same amount of energy.
The Third law
This law states that at absolute zero (the lowest temperature possible, -273.15ºC), the total entropy of a perfect crystal is zero. Absolute zero cannot be achieved, as by simply observing the temperature of the system, will raise the temperature of the system. Also, as the uncertainty principle states (this principle does not apply to classical physics as much), you cannot know both the exact location and the exact momentum of an particle. At absolute zero, atoms stop moving, as they have no thermal energy, and this allows you to know the momentum and location of a particle. So absolute zero is a theoretical concept.
The laws of thermodynamics originated in the 1800s, when people were trying to improve the efficiency of heat driven engines, such as the steam engine.
(above) Steam engine
These laws are some of the most important laws, as they explain the behaviour of energy. The second law even explains, in some regards, the entire concept of time.
There were originally three laws of thermodynamics, but in the 1935, another law was proposed. This law was thought to be more fundamental than the other laws, so it became the zeroth law.
The Zeroth Law
This law states that if two objects are in equilibrium (they are balanced, and in this case with energy) even though they are in contact, there is no change of energy in either object. The net flow of energy between the objects is zero.
The First Law
The first law states that in a closed or isolated system, the total amount of energy in the system will remain unchanged. The energy can be transformed from one form to another, but the overall level will remain the same. Energy is always conserved. The universe is, as far as we know, a closed system, so the energy in the universe is always the same.
The Second Law
The Second law states that the entropy (amount of disorder) of an isolated system always increases over time. Lets say that you have an isolated plastic container, half with hot soup in it, half with cold ice cream in it (low entropy). This law says that the temperature of the soup gets colder, and the temperature of the ice cream will get warmer, therefore becoming equal (high entropy). This law explains why if you drop ink in water, it will not un-mix. Because of this, some people think this how time works. The universe (a closed system) will always have increasing total amount entropy. The possible fate of the universe, as all matter will have the same amount of energy.
The Third law
This law states that at absolute zero (the lowest temperature possible, -273.15ºC), the total entropy of a perfect crystal is zero. Absolute zero cannot be achieved, as by simply observing the temperature of the system, will raise the temperature of the system. Also, as the uncertainty principle states (this principle does not apply to classical physics as much), you cannot know both the exact location and the exact momentum of an particle. At absolute zero, atoms stop moving, as they have no thermal energy, and this allows you to know the momentum and location of a particle. So absolute zero is a theoretical concept.
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