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Writer's pictureSaren

The First Law of Thermodynamics

Hello Everyone! Thanks for stopping by on this lovely day to learn about the first law of thermodynamics!


Why you should understand the first law of thermodynamics:

The first law of thermodynamics serves as a stepping stone for the rest of the unit in thermodynamics.


Main Ideas

- Define the First Law of Thermodynamics

- What does it mean

- Application of the First Law


Define the First Law of Thermodynamics

The first law of thermodynamics states that energy cannot be created or destroyed. Energy can only change forms. This means that in the entire universe, the same amount of energy exists. Since the system and surroundings make up the universe, all the energy in the universe is contained in the system and surroundings.


What does the First law mean

To understand how energy is exchanged from location to location, we have to understand the different forms of energy and where it can go. I would recommend checking out my post on an Introduction to Thermodynamics and Enthalpy before continuing into this topic. A strong foundation in the background concepts relating to thermodynamics

The first law states that energy is never created or destroyed, it only changes forms. This doesn't mean that heat energy or kinetic energy only changes locations, it can also change from one type of energy to another.


For example, chemical energy can change into heat energy which is called an exothermic reaction.


Applications

Below there is an image that depicts three different types of energy exchanges that I'm going to use to explain the first law of thermodynamics.


A flat iron heating up: A flat iron gives off heat which can be used to straighten hair. This is electrical energy (which is a form of chemical energy) being changed into chemical energy.


Ice melting: I use this example all the time because it really is a great example of thermodynamics. Ice melts because of an influx of heat energy from the surroundings. This heat is transferred into the ice which causes the kinetic energy of the molecules to increase. This increase in kinetic energy causes melting at the molecules within the ICE move farther apart.


A plant photosynthesizing: Light energy from the sun is transferred to plant causing photosynthesis. Photosynthesis takes light energy from the sun and uses it to create chemical energy in the form of glucose (sugar). The plant then uses this chemical energy to grow and reproduce.


Summary

- The first law of thermodynamics states that energy cannot be created or destroyed. Energy can only change forms.

- Energy can change locations but also can change forms.



I hope you've found this post about the first law of thermodynamics helpful. If you have any questions please comment on this post, email me, or comment on my youtube video below.


Saren



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