First law of thermodynamics

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The first law of thermodynamics is a statement derived from the law of conservation of energy, which states that energy cannot be created or destroyed; it can only be transferred or transformed from one form to another. This means that in a closed system, the total energy remains constant, although it can be converted from one form to another.

Examples

Photosynthesis

First law of thermodynamics example - photosynthesis
Plants convert light energy into chemical energy through photosynthesis, as described by the first law of thermodynamics | Image: Stock photo[●]

During photosynthesis, plants convert light energy into chemical energy by using the energy from sunlight to convert carbon dioxide and water into glucose and oxygen. This process is an example of the first law of thermodynamics, which states that the total amount of energy before and after the conversion remains constant.

Light bulb

First law of thermodynamics example - light bulb
When a light bulb is turned on, electrical energy is converted into light energy, which is possible due to the first law of thermodynamics | Image: Stock photo[●]

When an electric current passes through the filament of a light bulb, it causes the filament to heat up and emit light. This is an example of the conversion of electrical energy to light energy, and the first law of thermodynamics ensures that the total amount of energy before and after the conversion remains the same.

Hand rubbing

First law of thermodynamics example - hand rubbing
The heat generated by rubbing our hands together is an example of the conversion of mechanical energy to heat energy, following the first law of thermodynamics | Image: Stock photo[●]

Rubbing our hands together generates heat due to friction, which is an example of the conversion of mechanical energy to heat energy. The first law of thermodynamics ensures that the total amount of energy before and after the conversion remains constant.

Falling stone

First law of thermodynamics example - falling stone
The potential energy of a stone at the top of a hill is converted to kinetic energy as it falls, in accordance with the first law of thermodynamics | Image: Stock photo[●]

When a stone falls from the edge of a hill, it gains kinetic energy due to its motion, which is an example of the conversion of potential energy to kinetic energy. The first law of thermodynamics applies here, as the total amount of energy remains constant throughout the conversion.

Burning wood

First law of thermodynamics example - burning wood
When wood is burned, chemical energy is transformed into heat energy, which follows the first law of thermodynamics | Image: Stock photo[●]

Burning dry wood releases stored chemical energy and converts it into heat energy. This is an example of the conversion of chemical energy to heat energy, and the first law of thermodynamics ensures that the total amount of energy before and after the conversion remains constant.

Braking bicycle

First law of thermodynamics example - braking bicycle
When brakes are applied to a moving bicycle, mechanical energy is converted into heat energy, following the first law of thermodynamics | Image: Stock photo[●]

When brakes are applied to a moving bicycle, the mechanical energy is converted into heat energy due to the friction between the brake pads and the wheel. This is an example of the conversion of mechanical energy to heat energy, and the first law of thermodynamics states that the total amount of energy remains constant throughout the conversion.

Loudspeaker

First law of thermodynamics example - loudspeaker
A loudspeaker converts electrical energy into sound energy when turned on, and this process follows the first law of thermodynamics | Image: Stock photo[●]

The conversion of electrical energy to sound energy occurs when a loudspeaker is turned on. The electrical energy is used to power the speaker, which vibrates rapidly to produce sound waves. The total amount of energy before and after the conversion remains constant due to the first law of thermodynamics.

Pushing a book

First law of thermodynamics example - pushing a book
Pushing a book converts potential energy to kinetic energy, and the first law of thermodynamics dictates that the total amount of energy remains constant | Image: Stock photo[●]

Pushing a book with the hand is an example of the conversion of potential energy to kinetic energy. As the book is pushed, it gains kinetic energy due to its motion. The first law of thermodynamics applies here, as the total amount of energy remains constant throughout the conversion.

Microwave oven

First law of thermodynamics example - microwave oven
When activated, a microwave oven transforms electrical energy into heat energy, adhering to the principles of the first law of thermodynamics | Image: Stock photo[●]

Turning on a microwave oven results in the conversion of electrical energy to heat energy. The electrical energy is used to power the magnetron, which produces microwaves that heat up the food inside the oven. The first law of thermodynamics ensures that the total amount of energy before and after the conversion remains constant.

Falling coconut

First law of thermodynamics example - falling coconut
When a coconut falls from a tree branch, potential energy is converted to kinetic energy, and this process is governed by the first law of thermodynamics | Image: Stock photo[●]

When a coconut falls from a tree branch, its potential energy is converted into kinetic energy due to its motion. This is an example of the conversion of potential energy to kinetic energy, and the first law of thermodynamics applies here, as the total amount of energy remains constant throughout the conversion.

Related

Image credit

  • The stock photos used in this post are sourced from platforms like Pexels, Pixabay, Canva, etc. Due to the age of the images, their specific origins remain unknown.

External links

Deep

Learnool.com was founded by Deep Rana, who is a mechanical engineer by profession and a blogger by passion. He has a good conceptual knowledge on different educational topics and he provides the same on this website. He loves to learn something new everyday and believes that the best utilization of free time is developing a new skill.

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