Energy Conservation

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The law of energy conservation is one of the most important laws of science; it states that we can neither create energy nor destroy it. This means the total energy of the isolated system remains constant unless some energy is added from outside. However, there are devices that convert energy from one form to another. 


Modern civilization came into existence when people came to know the ways of transforming energy from one form to another, to perform their useful work. Some energy transformation energy examples are Electric motors and electric generators.


In this article, we are going to discuss the types of energy conversion, examples of energy conversion in daily life.


The Law of Energy Conservation

We know that for an isolated system, the total energy remains constant. Now, let’s focus on the common type of energies in Physics. 


Kinetic Energy: 

The energy possessed by a body/object because of its motion.

Potential Energy: 

This energy is viewed as energy due to the object’s position.

If we sum these two energies, together they form mechanical energy. Now, we will focus on energy conversion by taking energy transformation examples in daily life.

Energy Conversion 

Let’s consider an earth-ball system and assuming it is isolated:

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Let’s say this ball is in the air and in the absence of air, the gravitational potential energy possessed by it is U, and its kinetic energy K is zero.


Here, K.E. = 0, and P.E. = P


Now, if I let it fall on the earth, it hits the ground without bouncing back; in this situation, its gravitational potential energy becomes zero.

 

However, when it touches the ground, it won’t be stationary, which means there will be kinetic energy. 

So, in the final position, K. E. = K, and P.E. = 0.


What we can see here is that all the potential energy gets converted into kinetic energy as soon the ball touches the ground. 


We might have a question that when the ball sits on the ground without bouncing, which means all the energy is destroyed, but it doesn’t happen. So where did the energy go?


Well, the energy possessed by the ball hitting the ground gets transformed into thermal energy warming the ball and the ground. 


In another scenario, let’s suppose, there was an air resistance, then you might wonder that the ball may not fall with greater kinetic energy when it gets down to the earth. However, in this case, the ball falling will heat up the ball and the air molecules around it. So, air resistance is a dissipative force that transforms into thermal energy. 


Now, if we were to write the whole scenario in the form of an equation, then we have:


Initial kinetic energy + Initial Potential energy is equal to the Final kinetic energy + Final Potential energy. (Ignoring other factors like non-conservative forces or dissipative energy).

                             

K0+ U0 = Kf + Uf =>   ΔK +   ΔU


So, the change in kinetic energy = the change in potential energy; this is how energy conversion occurs in daily life.


Now, we will look at the energy transformation examples in real life.


Energy Conversion Examples in Daily Life

There are types of energy conversions examples, let’s talk about these one-by-one: 

  • Natural sources of energy like the Sun transforms nuclear energy into light energy and heat.

  • Our body converts chemical energy in our food to mechanical energy for making our body’s ability to perform day-to-day tasks.

  • An electric fan transforms electrical energy into kinetic energy, which we can feel in the form of cool air during summers.

  • Lightning occurs during heavy rainfall converts electrical energy into heat, light energy, and sound energy.

  • Chemical energy stored in the form of fuel converts into mechanical energy which is utilized in its propulsion.

  • The engine in the car converts the potential chemical energy present in gasoline and oxygen into thermal energy (heat), which is then transformed into the mechanical energy that accelerates the vehicle.


Now, let’s look at the types of energy transformations:


Types of Energy Transformations

  • Geyser -

It converts electrical energy into heat.

  • In a Steam Engine - 

The conversion of heat energy into mechanical energy takes place.

  • In an Electric Lamp - 

The electric energy is transformed into heat & light energy.

  • Photosynthesis - 

Solar energy is converted into chemical energy, which is utilized in the food formation process.

  • Electric Generator -

Transforms mechanical energy into electrical.

  • Electrical Motor - 

Transforms electrical energy into mechanical.

  • In Hydroelectric Dams - 

Transforms gravitational potential energy into electric energy.

  • In OTEC - 

Heat energy is converted into mechanical energy or mechanical energy.

  • Battery-Powered Torch Light -

In the battery - chemical energy converted into electric energy and in bulbs - electrical energy transforms into radiant energy.

  • Burning of Wood - 

While the wood is burning, the chemical energy transforms into heat and light energy.

  • While rubbing both the hands during winters, the kinetic energy transforms into thermal energy. 

FAQ (Frequently Asked Questions)

Question 1: List the Sets of Energy Transformations taking Place in Conventional Automobiles.

Answer: The following are the steps involved in energy transformation:

  • The chemical energy present in the fuel transforms into the kinetic energy of the expanded gas.

  • Now, the kinetic energy of the expanding gas converts into linear piston movement.

  • This linear piston movement converts into the rotatory crankshaft movement.

  • Finally, the rotatory movement of driving wheels coverts into or sets the car into linear motion. 

Question 2: List 10 types of Energy.

Answer: Below is the list of 10 types of energy:

  • Kinetic energy

  • Potential energy

  • Ionization energy

  • Mechanical energy

  • Nuclear energy

  • Chemical energy

  • Electromagnetic energy

  • Thermal energy

  • Sonic energy

  • Gravitational energy

Question 3: What is the most Efficient Form of Energy?

Answer: If we talk about energy in terms of efficiency, renewable energy is one of the most efficient forms of energy. Some of the renewable energy are listed below:

  • Hydro-electric energy

  • Solar energy

  • Wind energy

  • Hydro-thermal energy

  • Tidal energy


Out of the types of energies listed above, solar energy is proven to be the most efficient source of energy for home and commercial use.

Question 4: Are Energy Transformations 100% Efficient?

Answer: According to the first law of thermodynamics, the energy transformations are 100% efficient. It means the ratio of energy output to energy input is always unity. 

For example, In a device like an electric heater, the energy input is electricity, and the energy output is heat.