The first law of thermodynamics, also known as the law of conservation of energy, states that energy cannot be created or destroyed, only transformed from one form to another. This law has many practical applications in our day to day life. Here are a few examples:

Home Heating: The first law of thermodynamics is fundamental in understanding how heating systems work in our homes. When we heat our homes, we are converting electrical or chemical energy into thermal energy. The heat energy is then transferred to our living spaces, which raises the temperature of the room. The law of conservation of energy tells us that the amount of heat energy supplied to the room must equal the amount of energy consumed by the heating system.

Food Digestion: The first law of thermodynamics also applies to our bodies when we consume food. Food contains potential energy in the form of calories. When we eat, our bodies convert the food energy into thermal energy, which we use to fuel our daily activities. This energy conversion process is what allows us to move and perform work.

Power Generation: Power plants, such as coal-fired power plants, generate electricity by converting the potential energy in fossil fuels into electrical energy. The first law of thermodynamics tells us that the amount of energy output from the power plant must equal the amount of energy input from the fuel source.

Transportation: The first law of thermodynamics is also important in transportation systems. When we drive a car, the chemical energy stored in the fuel is converted into kinetic energy, which propels the car forward. The energy transformation is subject to the first law of thermodynamics, which tells us that the amount of energy output from the engine must equal the amount of energy input from the fuel.

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So, the first law of thermodynamics has many practical applications in our day to day life, from home heating to transportation systems. It is a fundamental law of nature that governs how energy is transformed and used in our world ;)

The Second Law of Thermodynamics is also of great importance and is the scientific basis for understanding many things in life. All processes result in an increase in total entropy and decrease in total free energy. It is essential to remember this when evaluating new energy systems and processes.

The Second Law in its Clausius entropy form presumes the First Law. The SL states that in any real process, the entropy of an isolated system increases between two thermal equilibrium states. One of the most important practical consequences of the SL is that where we can define the Isolated system (I.e. recognise its boundaries), the conversion of kinetic or thermal energy to mechanical energy is less than 100% efficient: However, the identification of the isolated system is not always straightforward. Neither a plant or the earth is an isolated system and the plant and the universe are not at thermal equilibrium so Clausius entropy cannot be defined.

The FIrst and Second Law do not prevent us from building a skyscraper three miles high. Economics and the wind might make this impractical, but if you spend enough energy, it is possible!

Perhaps the most important aspect of the 2LoT is that for ANY system and ANY process, the net change in entropy of the universe (system + surroundings) will be ≥0. People often like to make a huge deal about some particular process or some particular system in which the entropy of the *system* is reduced but never forget that the increase in entropy of the surroundings will always be greater than any decrease in entropy of that system such that the NET result is an increase. It's easy to create a system that reduces in entropy. Heat it up and then let it cool (i.e., transfer heat to the surroundings). When a cup of coffee cools off, the entropy of the coffee and cup are reduced but the entropy of the surroundings will be increased that much more. When a can of beer warms to room temperature, there is also a net increase in entropy. Nothing escapes the 2LoT. Do not believe stories about magical systems that circumvent the 2LoT.

Dudley, quite right. We should exercise caution on the use of the word 'universe' in relation to the SL. If one means 'our local part of the universe' - as in a reacting system (such as a chemical reaction in a test tube) and the immediate laboratory surroundings (bench, area, glass...) then we are safe. However, the universe in the sense of planets, stars, black holes, dark matter etc is obviously not at thermal equilibrium and so we cannot define its Clausius entropy. For this reason defining the SL in terms of the entropy of the wider universe is meaningless.

The First Law is the special case of the general energy conservation law. Energies can be divided into inner and outer ones. The 1. Law in a special meaning connects the two groups.

The first law of Thermodynamics basically relates to the law of conservation of energy where the total energy in a system remains constant yet the energy may be converted from one form to the other form. There are several examples we encounter in our day-to-day life:

Example: Electric energy is converted into light energy by an electric bulb, potential energy is converted into kinetic energy when a ball is thrown from a certain height and hits the ground, melting of ice cubes etc.

Feynman’s comments on energy and the FL give energy conservation a mysterious feel. Perhaps there is an analogy with mathematics where we struggle to explain why 2 + 2 = 4 but that doesn’t stop us using it. But perhaps that is a philosophical Avenue that takes us away from the question posed and for we have all being trying to answer.