Why Does Thunder follow Lighting?

During the rainy season we often see lightning in the sky followed by thunder. Do you know what this lightning is and how thunder follows it? In ancient times whenever man saw lightning in the sky and heard thunder he used to believe that gods were angry and punishing him for some sin. Benjamin Franklin was the first person who, in 1872, scientifically explained the occurrence of lightning. In fact, whenever the sky gets overcast with clouds, the small particles of water present in them get charged due to air friction. 

In the process, some clouds become positively charged, while some others negatively charged. When a positively-charged cloud approaches a negatively charged one. There develops a potential difference of millions of volts between them. Because of this high voltage, there is a sudden electric discharge through the air between the two clouds and a streak of light is seen. This is called 'lightning'. The electric discharge through the air produces a large amount of heat due to which the atmospheric air suddenly expands. 

Lighting. 

With this sudden expansion, the innumerable molecules of the air collide with one another producing sound. This is called 'thunder'. Although lightning and thunder are produced simultaneously, yet we see the flash of lightning first. It is so because the velocity of light is very high i.e.,300000 kms.per second. On the other hand velocity of sound is only 332 metres per second. Thus, because of its high velocity, light immediately reaches our eyes, but the sound takes some time to reach our ears.

Whenever a charged cloud passes by some tall tree or high building, by induction, it produces the opposite charge on that tree or building. When the amount of charge so produced is very high, there is a sudden electric discharge in the air. It is then said that lightning has struck such tree or building.

To protect high buildings from such mishaps pointed rods of copper or some other metal are fixed on the top of buildings which passes through them and are buried deep in the earth.

These are called 'lightning conductors'. Whenever some charged cloud passes by such a building and produces opposite charge on it, the charge goes to the earth through the rod and does not damage the building. This is how buildings are protected from the lightning. 

THERE IS A CRACK IN EVERYTHING, THAT'S HOW THE LIGHT GETS IN.

- LEONARD COMEN.

Why is the Tower of Pisa Leaning?

Is the Tower of Pisa Leaning?

Everybody knows that in the city of Pisa in Italy, there is a beautiful tower that "leans" Very ew people know the reason of its leaning Every year thousands of people go there to see the der made of white marble The walls are four meters thick at its base. It has eight story and in 55 meters high. There is a stairway which leads to the top and has 300 steps From as top one can have a magnificent view of the city and the sea which is ten kilometer away.   

Leaning Tower of Pisa, Italy.

Now the question arises: What makes this tower lean and why it does not fall? At the top, the tower is five  meters away from the perpendicular. It leans over by five meters If we drop ball from it's top, a would hit the ground five meters away from its base. It was intended as a bell tower for the cathedral which is nearby. Its construction was started in 1174 and completed in 1350 When the construction started nobody thought that it would lean, but it started leaning after the third story was completed. The foundations of the tower were laid sand and this may explain why it leans. Since the tower started leaning, the plans of its constructs were modified and the tower was completed. During the last one hundred years the tower has leaned another 30 cm.

Now the question arises: Even while leaning, why does it not tall?  According to science anything well remain stable till the vertical line drawn from its center of gravity passes through The center of gravity is that point where the whole of the mass of the body is  supposed to be concentrated. Till today the vertical line from the center of gravity has been falling within the base of the tower. That is why it has not fallen. It is believed that when the tower leans further and the line from its center of gravity pass out of its base, it will fall down According to some engineers the tower will definitely fall one day.  

Rome Wasn't Built In A Day. 

Sir Isaac Newton and The Foundations of Modern Physics.

Introduction

Isaac Newton, one of the most brilliant minds in the history of science, is renowned for his groundbreaking contributions to physics. His profound insights into the laws of motion and universal gravitation laid the foundation for classical mechanics and revolutionized our understanding of the physical world. In this article, we will explore the life and achievements of this iconic physicist, as well as his profound influence on the field of physics. 

Sir Isaac Newton (1643-1727) 

Early Life and Education

Isaac Newton was born on January 4, 1643, in Woolsthorpe, England. His early life was marked by hardship, as he grew up in a farming family following the premature death of his father. However, his exceptional intellect soon became evident, and he attended The King's School in Grantham, where his interest in mathematics and science first took root.

In 1661, Newton enrolled at Trinity College, Cambridge, where he embarked on a journey that would change the course of scientific history. At Cambridge, he delved into the study of mathematics and physics, laying the groundwork for his future groundbreaking discoveries.

Laws of Motion

Newton's three laws of motion, often referred to as Newton's Laws, are the cornerstone of classical mechanics. They describe the fundamental principles governing the motion of objects and remain integral to our understanding of the physical universe.

1. Newton's First Law of Motion: The Law of Inertia

Newton's first law states that an object at rest will stay at rest, and an object in motion will stay in motion at a constant velocity unless acted upon by an external force. In other words, an object will maintain its state of motion unless compelled to change by an unbalanced force.

This law fundamentally altered the way we perceive motion, introducing the concept of inertia, which is the tendency of objects to resist changes in their state of motion.

2. Newton's Second Law of Motion: The Law of Force and Acceleration

The second law of motion relates force, mass, and acceleration. It can be expressed mathematically as F = ma, where F represents force, m is the mass of the object, and a is its acceleration. This law elucidates the relationship between force and the rate of change of an object's velocity.

Newton's second law allowed for precise calculations of how forces influence the motion of objects, making it an invaluable tool in both science and engineering.

3. Newton's Third Law of Motion: The Law of Action and Reaction

Newton's third law posits that for every action, there is an equal and opposite reaction. In simpler terms, when one object exerts a force on another, the second object exerts an equal and opposite force on the first. This law is the foundation of the conservation of momentum and explains phenomena as diverse as rocket propulsion and walking.

Universal Gravitation

Newton's law of universal gravitation was a milestone in the history of science. Published in his work "Philosophiæ Naturalis Principia Mathematica" in 1687, it revolutionized our understanding of the force that governs the motion of celestial bodies.

The law of universal gravitation states that every mass attracts every other mass in the universe with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them. This discovery provided a unified explanation for the motion of the planets, the behavior of tides, and the falling of objects on Earth. It effectively merged terrestrial and celestial mechanics into a single coherent framework.

The Impact of Newton's Work

Isaac Newton's laws and theories radically transformed our understanding of the natural world. His work became the cornerstone of classical physics, and it still forms the basis of our scientific endeavors today. His influence is immeasurable, and here are a few areas where his legacy is most pronounced:

1. Astronomy: Newton's law of universal gravitation made it possible to calculate the orbits of planets and predict astronomical events, leading to the eventual discovery of Neptune and the exploration of outer space.

2. Engineering: Newton's laws of motion are foundational principles in engineering, allowing us to design everything from bridges to spacecraft with precision.

3. Modern Science: His methods of inquiry and mathematical rigor laid the groundwork for the scientific method and critical thinking in science.

4. Mathematics: Newton made significant contributions to mathematics, including the development of calculus, which is a fundamental branch of mathematics.

5. Physics: Newton's laws are still taught in every physics classroom, and while they have been refined with the advent of relativity and quantum mechanics, they remain incredibly accurate in everyday situations.

Conclusion

Isaac Newton's work revolutionized our understanding of the physical universe. His laws of motion and the law of universal gravitation have stood the test of time, remaining as critical pillars in the edifice of modern physics. Beyond his scientific contributions, Newton's methods of inquiry, dedication to empirical evidence, and commitment to mathematical rigor continue to inspire scientists and thinkers to this day. His life and work serve as a testament to the power of human intellect and the enduring impact of scientific exploration. As we celebrate the genius of Isaac Newton, we are reminded of the endless possibilities that await those who dare to inquire and explore the mysteries of the cosmos...  

No Great Discovery Was Ever Made Without A Bold Guess.  

Explanation of Photoelectric Effect and their Laws.

 Explanation for the Photoelectric Effect :

The experimentally observed facts of photoelectric effect can be explained the help of Einstein's photoelectric equation.

i) Each incident photon liberates one electron, then the increase of intensity of the light (the number of photons per unit area per unit time) increases the number of electrons emitted thereby increasing the photocurrent, The same has been experimentally observed.

ii) From K(max)=h v—Φ•, it is evident max that K is proportional to the frequency max of the incident light and is independent of intensity of the light.

iii) There must be minimum energy (equal to the work function of the metal) for incident photons to liberate electrons from the metal surface. ( h v= h v 1/2 mv^2 ). 

Below this value of energy, emission of electrons is not possible. Correspondingly, there exists minimum frequency called threshold frequency below which there is no photoelectric emission.

iv) According to quantum concept, the transfer of photon energy to the electrons is instantaneous so that there is no time lag between incidence of photons and ejection of electrons. Thus, the photoelectric effect is explained on the basis of quantum concept of light.

Laws of Photoelectric Effect :

i) For a given metallic surface, the emission of photoelectrons takes place only if the frequency of incident light is greater than a certain minimum frequency called the threshold frequency.

ii) For a given frequency of incident light above threshold value, the number of photoelectrons emitted is directly proportional to the intensity of the incident light. The saturation current is also directly proportional to the intensity of incident light. 

iii) Maximum kinetic energy of the photo electrons is independent of intensity of the incident light.

iv) Maximum kinetic energy of the photo electrons from a given metal is directly proportional to the frequency of incident light.

v) There is no time lag between incidence of light and ejection of photoelectrons. 

" When you change the way you look at things, the things you look at change. "

--- Max Planck.---