Sunday 12 June 2016

Who is Isaac Newton


Isaac Newton


Isaac Newton
Lived 1643 to 1727.
Isaac Newton is perhaps the greatest physicist who has ever lived. He and Albert Einstein are almost equally matched contenders for this title.
Each of these great scientists produced dramatic and startling transformations in the physical laws we believe our universe obeys, changing the way we understand and relate to the world around us.

Early Life and Education

Isaac Newton was born on January 4, 1643 in the tiny village of Woolsthorpe-by-Colsterworth, Lincolnshire, England.
His father, whose name was also Isaac Newton, was a farmer who died before Isaac Junior was born. Although comfortable financially, his father could not read or write.
His mother, Hannah Ayscough, married a churchman when Newton was three years old.
Newton disliked his mother’s new husband and did not join their household, living instead with his mother’s mother, Margery Ayscough.
His resentment of his mother and stepfather’s new life did not subside with time; as a teenager he threatened to burn their house down!
Beginning at age 12, Newton attended The King’s School, Grantham, where he was taught the classics, but no science or mathematics. When he was 17, his mother stopped his schooling so that he could become a farmer. Fortunately for the future of science Newton found he had neither aptitude nor liking for farming; his mother allowed him to return to school, where he finished as top student.
Servant and Undergraduate
In June 1661, aged 18, Newton began studying for a law degree at Cambridge University’s Trinity College, earning money working as a personal servant to wealthier students.
By the time he was a third-year student he was spending a lot of his time studying mathematics and natural philosophy (today we call it physics). He was also very interested in alchemy, which we now categorize as a pseudoscience.
His natural philosophy lecturers based their courses on Aristotle’s incorrect ideas from Ancient Greece. This was despite the fact that 25 years earlier, in 1638, Galileo Galilei had published his physics masterpiece Two New Sciences establishing a new scientific basis for the physics of motion.
Newton began to disregard the material taught at his college, preferring to study the recent (and more scientifically correct) works of Galileo, Boyle, Descartes, and Kepler. He wrote:
Isaac Newton“Plato is my friend, Aristotle is my friend, but my greatest friend is truth.”
ISAAC NEWTON
Mathematician and Physicist
Reading the works of these great scientists, Newton grew more ambitious about making discoveries himself. While still working part-time as a servant, he wrote a note to himself. In it he posed questions which had not yet been answered by science. These included questions about gravity, the nature of light, the nature of color and vision, and atoms.
After three years at Cambridge he won a four-year scholarship, allowing him to devote his time fully to academic studies.

A Mind on Fire

In 1665, at the age of 22, a year after beginning his four-year scholarship, he made his first major discovery: this was in mathematics, where he discovered the generalized binomial theorem. In 1665 he was also awarded his B.A. degree.
By now Newton’s mind was ablaze with new ideas. He began making significant progress in three distinct fields – fields in which he would make some of his most profound discoveries:
  • calculus, the mathematics of change, which is vital to our understanding of the world around us
  • gravity
  • optics and the behavior of light
He did much of his work on these topics back home at Woolsthorpe-by-Colsterworth after the Great Plague forced his college in Cambridge to close.

Fellow and Lucasian Professor of Mathematics

At the age of 24, in 1667, he returned to Cambridge, where events moved quickly.
First he was elected as a fellow of Trinity College.
A year later, in 1668, he was awarded an M.A. degree.
A year after that, the Lucasian Professor of Mathematics at Trinity College, Isaac Barrow, resigned and Newton was appointed as his replacement; he was just 26 years old. Barrow, who had recommended that Newton should succeed him, said of Newton’s skills in mathematics:
Isaac Barrow“Mr Newton, a fellow of our College, and very young, being but the second year master of arts; but of an extraordinary genius and proficiency.”
ISAAC BARROW
Mathematician

Isaac Newton’s Scientific Achievements and Discoveries

Achievements in Brief

Isaac Newton, who was largely self-taught in mathematics and physics:
  • generalized the binomial theorem
  • showed that sunlight is made up of all of the colors of the rainbow. He used one glass prism to split a beam of sunlight into its separate colors, then another prism to recombine the rainbow colors to make a beam of white light again.
  • built the world’s first working reflecting telescope.
  • discovered/invented calculus, the mathematics of change, without which we could not understand the behavior of objects as tiny as electrons or as large as galaxies.
  • wrote the Principia, one of the most important scientific books ever written; in it he used mathematics to explain gravity and motion. (Principia is pronounced with a hard c.)
  • discovered the law of universal gravitation, proving that the force holding the moon in orbit around the earth is the same force that causes an apple to fall from a tree.
  • formulated his three laws of motion –Newton’s Laws – which lie at the heart of the science of movement.
  • showed that Kepler’s laws of planetary motion are special cases of Newton’s universal gravitation.
  • proved that all objects moving through space under the influence of gravity must follow a path shaped in the form of one of the conic sections, such as a circle, an ellipse, or a parabola, hence explaining the paths all planets and comets follow.
  • showed that the tides are caused by gravitational interactions between the earth, the moon and the sun.
  • predicted, correctly, that the earth is not perfectly spherical but is squashed into an oblate spheroid, larger around the equator than around the poles.
  • Used mathematics to model the movement of fluids – from which the concept of aNewtonian fluid comes.
  • devised Newton’s Method for finding the roots of mathematical functions.
Isaac NewtonA cylinder of air reaching to the top of the atmosphere is of equal weight with a cylinder of water about 33 feet high.
ISAAC NEWTON

Some Details about Newton’s Greatest Discoveries

Newton revealed his laws of motion and gravitation in his book the Principia. Just as few people at first could understand Albert Einstein’s general theory of relativity, few people understood the Principia when it was published. When Newton walked past them one day, one student remarked to another:
“There goes a man who has written a book that neither he nor anybody else understands.”
Newton’s ideas were spread by the small number of people who understood the Principia, and who were able to convey its message in more accessible ways: people including Leonard Euler, Joseph Louis Lagrange, Pierre Simon de Laplace, Willem Jacob ‘s Gravesande, William Whiston, Voltaire, John Theophilus Desaguliers, and David Gregory.

Calculus

Newton was the first person to fully develop calculus. Calculus is the mathematics of change. Modern physics and physical chemistry would be impossible without it. Other academic disciplines such as biology and economics also rely heavily on calculus for analysis.
In his development of calculus Newton was influenced by Pierre de Fermat, who had shown specific examples in which calculus-like methods could be used. Newton was able to build on Fermat’s work and generalize calculus. Newton wrote that he had been guided by:
Isaac Newton“Monsieur Fermat’s method of drawing tangents.”
ISAAC NEWTON
Mathematician and Physicist
From Newton’s fertile mind came the ideas that we now call differential calculus, integral calculus and differential equations.
Soon after Newton generalized calculus, Gottfried Leibniz achieved the same result. Today, most mathematicians give equal credit to Newton and Leibniz for calculus’s discovery.

Universal Gravitation and the Apple

Newton and his appleNewton’s famous apple, which he saw falling from a tree in the garden of his family home in Woolsthorpe-by-Colsterworth, is not a myth.
He told people that seeing the apple’s fall made him wonder why it fell in a straight line towards the center of our planet rather than moving upwards or sideways.
Ultimately, he realized and proved that the force behind the apple’s fall also causes the moon to orbit the earth; and comets, the earth and other planets to orbit the sun. The force is felt throughout the universe, so Newton called it Universal Gravitation. In a nutshell, it says that mass attracts mass.
Newton discovered the equation that allows us to calculate the force of gravity between two objects.
Most people don’t like equations much: E = mc2 is as much as they can stand, but, for the record, here’s Newton’s equation:
newton gravity equation
Newton’s equation says that you can calculate the gravitational force attracting one object to another by multiplying the masses of the two objects by the gravitational constant and dividing by the square of the distance between the objects.
Dividing by distance squared means Newton’s Law is an inverse-square law.
Newton proved mathematically that any object moving in space affected by an inverse-square law will follow a path in the shape of one of the conic sections, the shapes which fascinated Archimedesand other Ancient Greek mathematicians.
For example, planets follow elliptical paths; while comets follow elliptical, or parabolic or hyperbolic paths.
And that’s it!
Newton showed everyone how to calculate the force of gravity between things such as people, planets, stars and apples.

Newton’s Laws of Motion

Action Reaction
Third Law: The rocket flies because of the upward thrust it gets in reaction to the high speed gas particles pushing downward from its engines.
Newton’s three laws of motion still lie at the heart of mechanics.
First law: Objects remain stationary or move at a constant velocity unless acted upon by an external force. This law was actually first stated by Galileo, whose influence Newton mentions several times in the Principia.
Second law: The force F on an object is equal to its mass m multiplied by its acceleration: F = ma.
Third law: When one object exerts a force on a second object, the second object exerts a force equal in size and opposite in direction on the first object.
With Newton’s calculus, universal gravitation, and laws of motion, you have enough knowledge at your fingertips to plot a course for a spaceship to any planet in our solar system or even another solar system!
And Isaac Newton figured it all out about 300 years before we actually did send a spaceship to the planets.
A Word of Caution
Newton’s laws become increasingly inaccurate when speeds reach substantial fractions of the speed of light, or when the force of gravity is very large. Einstein’s equations are then required to produce reliable results.

Optics and Light

Newton was not just clever with his mind. He was also skilled in experimental methods and working with equipment.
He built the world’s first reflecting telescope. This telescope focuses light from a curved mirror. Reflecting telescopes have several advantages over earlier telescopes including:
  • they are cheaper to make
  • they are easier to make in large sizes, gathering more light, allowing higher magnification
  • they do not suffer from a focusing issue associated with lenses called chromatic aberration.
Newton also used glass prisms to establish that white light is not a simple phenomenon. He proved that it is made up of all of the colors of the rainbow, which could recombine to form white light again.
Newton's two prism experiment.
Newton’s crucial 1672 experiment with two prisms. The result absolutely demolished competing theories, such as the proposal that glass added the colors to sunlight.

Alchemy, Feuds, Religion, and Planets Orbiting Distant Stars

Although he is one of the greatest scientists in history, Newton’s laboratory papers show that he probably devoted more of his time to alchemy than to anything we would recognize as science.
Not surprisingly, Newton never found the Philosophers’ Stone. Given his towering contributions to real science, all we can do is wonder what else he might have achieved if he had not been such a passionate alchemist.
Despite his brilliance, Newton was a very insecure man: most historians trace this back to his childhood family difficulties.
Newton published very little work until his later years, because in his early years as a scientist,Robert Hooke had disagreed strongly with a scientific paper Newton had published. Newton took criticism of his work in a very personal way and developed a lifelong loathing for Hooke.
His lack of published work also caused a huge issue when Gottfried Leibniz starting publishing his own version of calculus. Newton was already a master of this branch of mathematics, but had published very little of it. Again Newton’s insecurity got the better of him, and he angrily accused Leibniz of stealing his work. The pros and cons of each man’s case have long been debated by historians. Most mathematicians regard Newton and Leibniz as equally responsible for the development of calculus.
Newton was a very religious man with somewhat unorthodox Protestant Christian views. He spent a great deal of time and wrote a large body of private works concerned with theology and his interpretation of the Bible.
His scientific work had revealed a universe that obeyed logical mathematical laws. He had also discovered that starlight and sunlight are the same, and he speculated that stars could have their own systems of planets orbiting them. He believed such a system could only have been made by God.
Isaac NewtonThis most beautiful system of the sun, planets and comets could only proceed from the counsel and dominion of an intelligent and powerful Being. And if the fixed stars are the centers of other like systems, these, being formed by the like wise counsel, must be all subject to the dominion of One; especially since the light of the fixed stars is of the same nature with the light of the sun.
ISAAC NEWTON

Moving On

In 1696, Newton was appointed as a Warden of the Royal Mint. In 1700, he became Master of the Mint, leaving Cambridge for London, and more or less ending his scientific discovery work. He took his new role very seriously, going out into London’s taverns in disguise gathering evidence against counterfeiters.
In 1703, he was elected President of the Royal Society.
In 1705, he was knighted, becoming Sir Isaac Newton.
Albert Einstein“Nature to Newton was an open book, whose letters he could read without effort.”
ALBERT EINSTEIN
Theoretical Physicist

The End

Isaac Newton died on March 31, 1727, aged 84. He had never married and had no children.
He was buried in Westminster Abbey, London.

Who is Albert Einstein.


Albert Einstein


Albert Einstein
Lived 1879 – 1955.
Albert Einstein rewrote the laws of nature. He completely changed the way we understand the behavior of things as basic as light, gravity, and time.
Although scientists today are comfortable with Einstein’s ideas, in his time, they were completely revolutionary. Most people did not even begin to understand them.
If you’re new to science, you’ll probably find that some of his ideas take time to get used to!
Quick Guide to Albert Einstein’s Scientific Achievements
Albert Einstein:
• provided powerful confirmation that atoms and molecules actually exist, through his analysis of Brownian motion.
• demonstrated the photoelectric effect, establishing that light can behave as both a wave and a particle. Light particles (he called them quanta) with the correct amount of energy can eject electrons from metals.
• proved that everyone, whatever speed we move at, measures the speed of light to be 300 million meters per second in a vacuum. This led to the strange new reality that time passes more slowly for people traveling at very high speeds compared with people moving more slowly.
• discovered the hugely important and iconic equation, E = mc2, which showed that energy and matter can be converted into one another.
• rewrote the law of gravitation, which had been unchallenged since Isaac Newton published it in 1687. In his General Theory of Relativity, Einstein:
    » showed that matter causes space to curve, which produces gravity.
    » showed that the path of light follows the gravitational curve of space.
    » showed that time passes more slowly when gravity becomes very strong.
• became the 20th century’s most famous scientist when the strange predictions he made in hisGeneral Theory of Relativity were verified by scientific observations.
• spent his later years trying to find equations to unite quantum physics with general relativity. This was an incredibly hard task for him to set himself. To date, it has still not been achieved.

His Beginnings

Albert Einstein was born on March 14, 1879 in Ulm, Germany. He was not talkative in his childhood, and until the age of three, he didn’t talk much. He spent his teenage years in Munich, where his family had an electric equipment business. As a teenager, he was interested in nature and showed a high level of ability in mathematics and physics.
Einstein loved to be creative and innovative. He loathed the uncreative spirit in his school at Munich. His family’s business failed when he was aged 15, and they moved to Milan, Italy. Aged 16, he moved to Switzerland, where he finished high school.
In 1896 he began to study for a degree at the Swiss Federal Institute of Technology in Zurich. He didn’t like the teaching methods there, so he bunked classes to carry out experiments in the physics laboratory or play his violin. With the help of his classmate’s notes, he passed his exams; he graduated in 1900.
Einstein was not considered a good student by his teachers, and they refused to recommend him for further employment.
Einstein 1903
Einstein 1903
While studying at the Polytechnic, Einstein had learned about one of the biggest problems then baffling physicists. This was how to marry togetherIsaac Newton’s laws of motion with James Clerk Maxwell’s equations of electromagnetism.
In 1902 he obtained the post of an examiner in the Swiss Federal patent office, and, in 1903, he wedded his classmate Mileva Maric. He had two sons with her but they later divorced. After some years Einstein married Elsa Loewenthal.

Early Scientific Publications

Einstein continued to work in the patent office, during which time he made most of his greatest scientific breakthroughs. The University of Zurich awarded him a Ph.D. in 1905 for his thesis “A New Determination of Molecular Dimensions.”

1905: The Year of Miracles

In 1905, the same year as he submitted his doctoral thesis, Albert Einstein published four immensely important scientific papers dealing with his analysis of:
  • Brownian motion
  • the equivalence of mass and energy
  • the photoelectric effect
  • special relativity
Each of these papers on their own was a huge contribution to science. To publish four such papers in one year was considered to be almost miraculous. Einstein was just 26 years old.

Mass Energy Equivalence

Einstein gave birth in 1905 to what has become the world’s most famous equation:
E = mc2
The equation says that mass (m) can be converted to energy (E). A little mass can make a lot of energy, because mass is multiplied by c2 where c is the speed of light, a very large number.
A small amount of mass can make a large amount of energy. Conversion of mass in atomic nuclei to energy is the principle behind nuclear weapons and explains the sun’s source of energy.

The Photoelectric Effect

If you shine light on metal, the metal may release some of its electrons. Einstein said that light is made up of individual ‘particles’ of energy, which he called quanta. When these quanta hit the metal, they give their energy to electrons, giving the electrons enough energy to escape from the metal.
Einstein showed that light can behave as a particle as well as a wave. The energy each ‘particle’ of light carries is proportional to the frequency of the light waves.

Einstein’s Special Theory of Relativity

In Einstein’s third paper of 1905 he returned to the big problem he had heard about at university – how to resolve Newton’s laws of motion with Maxwell’s equations of light. His approach was the ‘thought experiment.’ He imagined how the world would look if he could travel at the speed of light.
He realized that the laws of physics are the same everywhere, and regardless of what you did – whether you moved quickly toward a ray of light as it approached you, or quickly away from the ray of light – you would always see the light ray to be moving at the same speed – the speed of light!
This is not obvious, because it’s not how things work in everyday life, where, for example, if you move towards a child approaching you on a bike he will reach you sooner than if you move away from him. With light, it doesn’t matter whether you move towards or away from the light, it will take the same amount of time to reach you. This isn’t an easy thing to understand, so don’t worry about it if you don’t! (Unless you’re at university studying physics.) Every experiment ever done to test special relativity has confirmed what Einstein said.
If the speed of light is the same for all observers regardless of their speed, then it follows that some other strange things must be true. In fact, it turns out that time, length, and mass actually depend on the speed we are moving at. The nearer the speed of light we move, the bigger differences we seen in these quantities compared with someone moving more slowly. For example, time passes more and more slowly as we move faster and faster.

Einstein Becomes Known to the Wider Physics Community

As people read Einstein’s papers and argued about their significance, his work gradually gained acceptance, and his reputation as a powerful new intellect in the world of physics grew. In 1908 he began lecturing at the University of Bern, and the following year resigned from the Patent Office. In 1911 he became a professor of physics at the Karl-Ferdinand University in Prague, before returning to Zurich in 1912 to a professorship there.
Working on the general theory of relativity, in 1911 he made his first predictions of how our sun’s powerful gravity would bend the path of light coming from other stars as it traveled past the sun.

The General Theory of Relativity – Einstein Becomes Famous Worldwide

A very, very rough approximation: the earth’s mass curves space. The moon’s speed keeps it rolling around the curve rather than falling to Earth. If you are on Earth and wish to leave, you need to climb out of the gravity well
Einstein published his general theory of relativity paper in 1915, showing, for example, how gravity distorts space and time. Light is deflected by powerful gravity, not because of its mass (light has no mass) but because gravity has curved the space that light travels through.
In 1919 a British expedition traveled to the West African island of Principe to observe an eclipse of the sun. During the eclipse they could test whether light from far away stars passing close to the sun was deflected. They found that it was! Just as Einstein had said, space truly was curved.
On November 7, 1919, the London Times’ headline read:
Revolution in science – New theory of the Universe – Newtonian ideas overthrown.

Honors and More Honors

Albert Einstein was awarded the Nobel Prize in Physics in 1921. People are sometimes surprised to learn that the award was not made for his work in special or general relativity, but for his overall services to theoretical physics and one of the works from his miracle year specifically – the discovery of the law of the photoelectric effect in 1905.
The Royal Society of London awarded him its prestigious Copely Medal in 1925 for his theory of relativity and contributions to the quantum theory. The Franklin Institute awarded him with the Franklin medal in 1935 for his work on relativity and the photo-electric effect.
Universities around the world competed with one another to award him honorary doctorates, and the press wrote more about him than any other scientist – Einstein became a celebrity.

Einstein’s Later Years

Einstein made his greatest discoveries when he was a relatively young man.
In his later years he continued with science, but made no further groundbreaking discoveries. He became interested in politics and the state of the world.
Einstein had been born German and a Jew. He died an American citizen in 1955. Einstein was in America when Hitler came to power. He decided it would be a bad idea to return to Germany, and renounced his German citizenship. Einstein did not practice Judaism, but strongly identified with the Jewish people persecuted by the Nazi Party, favoring a Jewish homeland in Palestine with the rights of Arabs protected.
It was Einstein’s wish that people should be respected for their humanity and not for their country of origin or religion. Expressing his cynicism for nationalistic pride, he once said:
“If relativity is proved right the Germans will call me a German, the Swiss will call me a Swiss citizen, and the French will call me a great scientist. If relativity is proved wrong, the French will call me Swiss, the Swiss will call me a German, and the Germans will call me a Jew.”

10 Most Famous Scientific Theories That Were Later Debunked By Scientist.

The most genuine merit of science is probably its readiness to admit if it preaches or reveals something wrong. The theories in science are always being reconsidered and scrutinized. Modern research often rejects old ideas, hoaxes and myths.

Today’s post on our Science Blog will discuss ten of the most popular and influential scientific discoveries that were based on dubious data, and were consequently proven wrong, debunked and replaced with more reliable and logical modern theories.

1- Fleischmann–Pons’s Nuclear Fusion

Cold fusion is a supposed kind of nuclear reaction that would occur at relatively low temperatures compared with hot fusion. As a new type of nuclear reaction, it gained much popularity after reports in 1989 by famous electrochemists Stanley Pons and Martin Fleischmann. The craze about cold fusion became weaker as other scientists, after trying to repeat the experiment, failed to get similar results.

2- Phrenology

Now widely considered as a pseudoscience, phrenology was the study of the shape of skull as indicative of the strengths of different faculties. Modern scientific research wiped it out by proving that personality traits could not be traced to specific portions of the brain.

3- The Blank Slate

The Blank Slate theory (or Tabula rasa), widely popularized by John Locke in 1689, proposed that individuals are born without built-in mental content and that their knowledge comes from experience and perception. Modern research suggests that genes and other family traits inherited from birth, along with innate instincts of course, also play a very important role.

4- Luminiferous Aether

The aether (or ether) was a mysterious substance that was thought to transmit light through the universe. The idea of a luminiferous aether was debunked as experiments in the diffraction and refraction of light, and later Einstein’s special theory of relativity, came along and entirely revolutionized physics.

5- Einstein’s Static (or Stationary) Universe

A static universe, also called a “stationary” or “Einstein” universe, was a model proposed byAlbert Einstein in 1917. It was problematic from the beginning. Edwin Hubble’s discovery of the relationship between red shift obliterated it by completely demonstrating that the universe is constantly expanding.

6- Martian Canals

The Martian canals were a network of gullies and ravines that some 19th century scientists erroneously thought to exist on Mars. First detected in 1877 by Italian astronomer Giovanni Schiaparelli, modern telescopes and imaging technology completely debunked the myth. The “canals” were actually found to be a mere optical illusion.

7- Phlogiston Theory

First postulated in 1667 by German physician Johann Joachim Becher, Phlogiston Theory is an obsolete scientific theory regarding the existence of “phlogiston”, a fire-like element, which was contained within combustible bodies and released during combustion. The theory tried to explain burning processes such as combustion and the rusting of metals, which are now jointly termed as “oxidation”.

8- The Expanding or Growing Earth

The Expanding Earth or Growing Earth is a hypothesis suggesting that the position and relative movement of continents is dependent on the volume of the Earth increasing. Modern science has turned down any expansion or contraction of the Earth.

9- Discovery of the Planet Vulcan

A small planet that was supposed to exist in an orbit between Mercury and the Sun, French mathematician Urbain Jean Joseph Le Verrier coined the name “Vulcan” while trying to explain the nature of Mercury’s orbit. No such planet was ever discovered, while the orbit of Mercury was explained in detail by Albert Einstein’s theory of general relativity.

10- Spontaneous (or Equivocal) Generation

Spontaneous generation or equivocal generation is an obsolete principle concerning the origin of life from inanimate matter. The hypothesis was brought out by Aristotle who advocated the work of earlier natural philosophers. It was proven wrong in the 19th century by the experiments of Louis Pasteur, drawing influence from Francesco Rediwho was an early proponent of germ theory and cell theory.

CAUSES OF SPORT INJURY.

Everyone from well-conditioned athletes to weekend warriors can suffer a sport injury
Weakness in the muscles, ligaments and tendons following vigorous exercise is often caused by inadequate fitness and a failure to warm-up properly as well as engaging in an activity you’re not properly conditioned for yet.  This is often a cause of injury.
When muscles are not used regularly muscle wasting can occur, meaning the muscle fibres have become weakened, so when you do attempt to engage in vigorous exercise beyond your physical capability you may feel tired quickly and this can lead to injury.
The good news however is that with regular exercise and training the muscles will adapt and strengthen. Poor flexibility is another factor in unconditioned athletes behind a sports-related injury.
Flexibility is important because it affects how the body moves. Muscles work together to create smooth movement, so if there is tightness or inflexibility in one muscle it can directly affect the opposing muscle and limit range of motion, which in time can weaken the muscles and the joint.
Over time these muscle imbalances can affect posture and can cause injury.
The best way to improve flexibility is through regular stretching exercises, either static or dynamic. If you struggle with flexibility these should be a daily part of your routine. A thorough warm-up is also essential to prepare the muscles and joints for exercise.
There are, however, different causes behind different sports injuries. These are the most common:
Overtraining
Simply put, this is doing too much, too often with insufficient rest between. A lack of adequate recovery time coupled with amplified intensity of training is the most common cause of overtraining.
Symptoms include:
- Excessive fatigue
- Troubled sleep
- Inability to concentrate
- Inability to perform the exercise or sport with the correct technique.
A physiological sign of overtraining is also an increased resting heart rate. The best way to avoid overtraining is to ensure adequate rest between sessions.
Overuse
Repetitive strain injuries are caused by repeated actions which apply pressure to a certain group of muscles, joint or area of soft tissue. 
They usually worsen over time and include injuries such as tennis elbow, golfer’s knee, thrower’s shoulder (impingement syndrome), plantar fasciitis and jumper’s knee (patellar tendonitis).
Symptoms include:
- Gradual pain which worsens over time, sometimes with swelling and/or bruising. Ensuring adequate rest between sessions is the best way to avoid an overuse injury.
Improper warm-up
Failure to perform a proper warm-up can put you at risk for injury as the muscles and joints are not prepared for exercise.  A warm-up is necessary to increase body temperature and circulation of blood to the muscles.
A 15-20 minute warm-up should include a combination of stretching and cardiovascular exercises to prepare the body for exercise, increases performance levels and helps to prevent injuries.
Poor technique
Any exercise or sport which is performed repetitively with bad form is a recipe for injury.  
Over time the symptoms of injuries being caused by improper technique will be exacerbated and can either lead to a more serious condition or result in more acute injuries.
The best way to avoid repeatedly performing an exercise/sport with the incorrect technique is to make sure you use a professional coach or trainer to show you the correct way to do things from the beginning and to ensure you’re wearing to appropriate clothing, shoes and using the right equipment.
Impact
Perhaps the hardest to avoid, sports injuries caused by impact are most common in contact sports such as football, rugby and boxing etc.
The impact of coming into hard contact with another person/object can force unnatural or unexpected twisting and quick direction-change which can in turn cause damage to connective tissue or even joint dislocation.
Common injuries here include cuts, bruising,head injury, muscle pain and dislocated joints, spinal injuries, ligament and tendon damage, fractures and head and spinal injuries.
As impact and contact is often a requirement of many sports the only way to reduce the risk is to wear protective clothing if possible, such as shin pads or helmets.  

Jesus kingdom VS Muhammad's kingdom.

Jesus’s arrest was the second in a series of pivotal events that led directly to His death.  Many Jewish leaders wanted Him dead and many Jewish supporters loved Him, and at least one, Peter, fought and was willing to die for Him.  Pointedly, Jesus told Peter to stop fighting.
A short time later Jesus stated:
“My kingdom is not of this world. If My kingdom were of this world, then My servants would be fighting so that I would not be handed over to the Jews; but as it is, My kingdom is not of this realm.” Therefore Pilate said to Him, “So You are a king?” Jesus answered, “You say correctly that I am a king.   (John 18:36).

Jesus did not intend to set up a physical kingdom.  Not only was it not one of his goals, He resisted the effort to do so.  In contrast to this, Jesus taught previously that He, as the Messiah, the Son of God, would return as the King and Judge and purge evil people from His kingdom.  (Matthew 13:40-43, 25:31-46, 26:63, 64, also ref. Daniel 7:13, 14, 27).  But for now the Messiah’s kingdom was going to have to wait.  One day it would be established, but not today, not during His life. 
There was another kingdom Jesus taught about: the “kingdom of God.”  A comparison of His teachings on His future kingdom with His teachings on the “kingdom of God” shows that more emphasis was placed on the “kingdom of God” theme.  This theme was prominent in His teaching, parables, and sermons.  The kingdom of God was present on earth, it existed in the here and now, and would be established in a fuller measure when He returned as the Word of God, the King of Kings and Lord of Lords.  This significant theme was one of the primary topics He taught following His resurrection (Acts 1:3).
Note however, even after His resurrection His disciples wanted and expected an established physical kingdom (Acts 1:7).  This kingdom would at the very least supplant Roman rule.  These disciples wanted earnestly to establish God’s rule on earth.  They rued Rome’s rule over and oppression of their country.  But they were answered “not now” and that that time was in the Father’s hands.  Then they were instructed on their lives’ mission and purpose.  From then on the physical kingdom of God on earth was not their goal or their vision.
Jesus instructed His disciples extensively about the kingdom of God because He desired that it be established and fulfilled in their lives.  Until He returned it was to be a spiritual kingdom, a spiritual power.  It is righteousness, peace, and joy in the Holy Spirit (Romans 14:17); it is where God is King.  God, through the Holy Spirit, was to rule as King in their hearts, souls, strengths, and minds.
As God ruled in people’s hearts and minds they changed.  Jesus’s two great commands were to love God and love your neighbor.  Men and women who became Christians were commanded to excel at this.  Those who became Christians turned from sin and hate towards loving God and man.  Their hearts and minds changed as they loved and obeyed Christ.  This submission to God was powerful enough to cause them to not only live for Him; it motivated them to suffer and die for Him.
During the next few centuries Christianity was persecuted harshly but it spread throughout the Roman Empire.  The kingdom of God was established in the hearts and minds of the early church and their faith and love won an empire.  No claim of moral perfection is made here, rather the changing of hearts and minds, and lives, under the kingdom of God’s rule is demonstrated.  This victory was won without the use of the sword, without threat, without coercion, without promise of material gain.  Force was not used to make people believe in Christ as the Messiah, the Son of God, and Lord.  No bigoted forms of taxation, social humiliation, or discrimination were imposed to provoke people to become Christians.  Under severe persecution Christianity continued to spread far and wide.
Why didn’t Jesus instruct His followers to establish a physical kingdom on earth?  They were willing to pick up swords.  Perhaps they could establish it for the Messiah’s rule?  Imagine a true Christian kingdom, a sanctified country, whose citizens excelled at loving God and loving their neighbor. This kingdom of God on earth would be a geo-political kingdom, a cultural and social kingdom, a martial kingdom.  There the church could establish, and if need be, enforce their beliefs and rules on non-Christians.
Why didn’t Jesus instruct His disciples to establish a theocracy or an ecclesiocracy?
“What could go wrong?”
Perhaps something like these monks fighting each other at the Church of the Nativity? Fighting Monks

How shameful.  How embarrassing.  What a brilliant crimson stain upon Christianity.  Atheists, Muslims, and others rightly use these public actions to criticize Christianity.  Christianity’s birthplace was in Jerusalem but these men are not practicing the Christianity Jesus and His disciples practiced.  They certainly do not represent a root of Christianity; their fruit is carnal. 
Yes, “What could go wrong?”


 MUHAMMAD’S KINGDOM & THE CALIPHATE
Muhammad’s ministry lasted for 23 years, from 610 to his death from poisoning in 633.  During that time, with the exception of his colossal Satanic Verses error, he proclaimed and practiced Islam faithfully.  Those 23 years were divided between two cities: 13 years in Mecca and 10 years in Medina.
Muhammad’s ministry in Mecca was primarily a spiritual one.  In several aspects it paralleled Jesus’s ministry.  At this time he did not seek to establish a physical kingdom of Allah.  (I know that Allah means God and Arab Christians use it.  Here I am using Allah to signify Islam’s God).  Allah had told Muhammad that he was not to force men to become Muslims:
“And if your Lord had enforced His Will, surely, all who are in the earth would have believed together. Will you then force men to become believers?”  Quran 10:99

Muhammad had little success in Mecca.  His few followers were weak and oppressed.  Any use of force against the Quraysh, the dominant tribe in Mecca, would result in their deaths.
However a few years before he left Mecca he gained new converts in Medina.  These followers preached Islam and gained many converts there.  Soon Muhammad had a sizeable body of Muslims in Medina.  Many were men of war and at the Second Pledge of Aqabah they pledged their swords in Muhammad’s defense.
Throughout his ministry, as Muhammad’s circumstances changed Allah’s revelations changed, and Islam changed.  And these fighting men represented a significant change!  Unlike his followers in Mecca the Medina Muslims were not weak or oppressed.  They were armed and knew how to fight.  On cue, shortly before he left Mecca and fled to Medina, Allah gave Muhammad a new revelation, the “Order to Fight.”  Ibn Ishaq states:
The apostle had not been given permission to fight or allowed to shed blood before the second Aqaba. He had simply been ordered to call men to God and to endure insult and forgive the ignorant….
…He gave permission to His apostle to fight and to protect himself against those who wronged them and treated them badly.1

The “Order to Fight” is described on pages 212 and 213.  Different Islamic scholars have differing opinions as to which verses exactly comprise this revelation (most all of the various verses are similar), but here the general text is stated as 22:39-41 and 2:193.  Below are two of the four verses
Permission to fight is given to those (i.e. believers against disbelievers), who are fighting them, ... 22:39
Fight against them until idolatry is no more and God’s religion reigns supreme.  But if they desist, fight none except the evil-doers. 2:193

The order to fight allowed both defensive and offensive fighting, (offensive to end idolatry and spiritual rebellion).  Many of the non-violent verses in the Quran were now "abrogated" or canceled.
Muhammad summed up Allah’s directive:
It has been narrated on the authority of Abdullah b. 'Umar that the Messenger of Allah said: I have been commanded to fight against people till they testify that there is no god but Allah, that Muhammad is the messenger of Allah, and they establish prayer, and pay Zakat and if they do it, their blood and property are guaranteed protection on my behalf except when justified by law, and their affairs rest with Allah.2

I want to emphasize this:  If you want to understand the violence in the Islamic would today you must start here.  Muhammad’s statement above is a foundation, a “Maxwell’s Equation,” for understanding the role violence plays in Islam.
Muhammad intended to set up a kingdom of Allah.  People would have to testify that Muhammad was Allah’s Messenger and they would have to obey various aspects of Islamic law.  This was not optional.  People had to either submit to Islam or fight the Muslims.  Muhammad, and implicitly his followers, were ordered to fight non-Muslims until they either converted or submitted to Islam’s rule (as Christians and Jews had to pay extortion and submit in humility per 9:29).

Muhammad establishes Allah’s kingdom on earth.
Muhammad heeded this new direction from Allah and put it into effect quickly.  He obeyed Allah and fought non-Muslims until they bent the knee to him.  He established Allah’s kingdom on earth.  How did he accomplish this?
Shortly after arriving in Medina Muhammad began to send out his soldiers to raid and pillage non-Muslim villages and trade caravans.  Naturally this led to them murdering non-Muslims.  Muhammad’s thefts and murders led to war.  Tabari records:
This incident had provoked (a state of) war between the Messenger of God and Quraysh and was the beginning of the fighting in which they inflicted casualties upon one another...3
Tabari notes that it was Muhammad, not the Quraysh, that started the war.  During the next ten years the breath, width, and depth of violence increased.  Below is a general progression of Muhammad’s efforts to obey Allah and spread Islam’s domain through the use of force, or threat of force, primarily:
1)  raids on non-Muslim villages and caravans
2)  murders and assassinations throughout the Hijaz
3)  targeted religious persecutions of several Jewish tribes within and without Medina
4)  military conquests, subjection, rapes, massacres, and total destruction of non-Muslim Arab tribes
5)  military campaigns to spread Islam’s domination far and wide.

Muhammad did not win all of his battles but he won most of them.  People feared Muhammad and the Muslims.  Muhammad’s military leaders proclaimed:  “Accept Islam and you will be safe.”  People understood that if they did not accept Islam then they were fair game to be attacked, plundered, tortured, enslaved, raped, and murdered.  Consequently many Arab tribes used the “if you can’t beat em, join em” approach to becoming Muslim.  They didn’t want to be plundered, have their wives stolen, enslaved and raped, they didn’t want their children made into slaves, they didn’t want to die.  Why not join Islam then?  And all of this occurred under Muhammad’s direction and approving eye.

The trail of oppression and blood behind Muhammad grew ever wide.  Muhammad took Allah’s command seriously and labored to fulfill that command:  he spread and established his Islam, the kingdom of Allah.  While he lived no one dared disobey him.  He ruled Allah’s kingdom firmly, continued to obey Allah, and fight men until Islam ruled over them.  He and his followers engaged in jihad, holy warfare, to spread his kingdom’s domain.  (Jihad means struggle or effort, but its theological definition is “holy warfare” 
He died about a year and a half after his conquest of Mecca.  He was an eminently successful man:  he had wealth, power, fame, respect, sex with many beautiful women, both wives and slave concubines.  He had overcome incredible challenges and eventually subjected or crushed his enemies.  Muhammad died at the apex of his power and he established Allah’s kingdom on the bodies of those who opposed or rejected his claim of prophethood.
But what happened after Muhammad died?  We’ll take a look at the kingdom of Allah in action.  What was its power?  What were its effects?


An examination of the Caliphate, the continuing “Kingdom of Allah.”
Muhammad left behind him a body of men that knew him, loved him, and obeyed him.  They would fight, kill, and die for him because they believed him to be a true prophet.  They had memorized his Quran, they recorded anecdotes about his life and teachings (hadith), and they imitated his lifestyle (sunnah) earnestly.  There was no shortage of knowledge about Muhammad’s example and his commands to love one another as brothers.  The men that led the Muslims after his death were not a pack of novices; they knew him and his will intimately.

ABU BAKR
Immediately following Muhammad’s death the Muslims began to quarrel amongst themselves over who would be their leader.  The original Muslims from Mecca, (the Muhajirun, “immigrants”), wanted one of their own to assume command as Caliph, while the Medina Muslims, (the Ansar, “helpers”), wanted one of their own, Sa’d bin ‘Ubadah, to be the leader.  An ugly argument broke out and each side cursed and threatened to kill the other.  Punches were thrown, and swords drawn but not used.  Umar proclaimed that Abu Bakr should be the leader and demanded that everyone give him the oath of allegiance willingly or unwillingly.  Finally the Ansar agreed to have Abu Bakr as ruler.
Quite an inauspicious start for them wasn’t it?  So much for the Muslim brotherhood that Muhammad taught and commanded.  Not much to be proud of.  This start was a portent of things to come.
Also following Muhammad’s death many tribes that had been subjected, coerced, or forced into becoming Muslims under compulsion, “willingly or unwillingly”, left Islam to one degree or another.  Many were not at war with the Muslims.  They wanted to live in peace and freedom instead of being forced to be Muslims.  However, under Islam they were viewed as apostates and Muhammad commanded the killing of apostates.  Consequently these tribes that refused to walk to Abu Bakr’s Islamic talk were attacked, re-subjected, or slaughtered.  Tens of thousands were killed by Abu Bakr’s Islamic army.  These wars are known as the wars of apostasy, (Ridda Wars).  Tabari volume 10 describes these brutal, imperial, wars in detail.
Some people doubt that the Muslims used compulsion and forced people to submit to Islam.  But that use of force is documented clearly:
“You [Muslims] were the most severe people against his enemies who were among you, and the most troublesome to his enemies who were not from among you, so that the Arabs became upright in God’s cause, willingly or unwillingly, and the distant one submitted in abject humiliation until through you God made great slaughter in the earth for His Apostle, and by your swords the Arabs were abased for him.”4

Muslims quote 2:256 as saying that there is no compulsion in religion but that verse was spoken for a specific time and a specific situation and it was definitely not a universal command with universal application.
Abu Bakr continued Muhammad’s methods of war and oppression to establish Allah’s kingdom and compel or force people to submit to Islam.
That of course was an external trait of Allah’s kingdom – conquering all that is non-Islamic.  But what about affairs of the heart?  How was Allah’s kingdom internalized?  How did it compare to Jesus’s “kingdom of God?”
The answer to his is best displayed in how Muhammad’s closest followers behaved and acted towards each other.  The early Christians were generally humble and devoted to each other and they served each other.  How about Muhammad’s family?  There we should expect to see the fullest measure of Allah’s kingdom in their lives and hearts.
But you would be surprised to see what actually happened.  Family and friends turned upon each other.  Betrayals, murders, assassinations, lust for power, greed, etc. all were prominent in the lives of Muhammad’s closest family and friends. 
For example, Muhammad had amassed a sizeable amount of wealth prior to his death.  Before his death Muhammad established that a large portion of it be used in support of the Muslim community and that his wives be provided for but he also ordered that his descendants were not to inherit any of the wealth because he believed that is what the Jewish prophets of old had done (he was wrong in this belief).  Consequently, upon becoming Caliph, Abu Bakr refused to distribute any of the wealth to Muhammad descendants.
This led to deep rooted strife and bickering.  Muhammad’s daughter, Fatimah, her husband Ali, and her relative al-Abbas, bickered with Abu Bakr and demanded the wealth.  He refused to give them a nickel.  As a result Fatimah and the other hated him deeply.  Fatimah died six months after Muhammad.  Ali’s hate was such that he did not even tell Abu Bakr about her death nor allow him to attend her burial.5
You can see from this episode that these people had not been transformed from their carnal selves.  Muhammad’s kingdom had changed their outsides, they grew wealthy and powerful, but their hearts were unregenerate and sinful.
Abu Bakr was Caliph up to his death about a year and a half later.  He was Muhammad’s best friend and knew him best.  Certainly Abu Bakr did what Muhammad expected him to do.  Abu Bakr shed a river of blood to spread and maintain Allah’s kingdom, Islam. 

UMAR
Abu Bakr was wise enough to preclude the violence and stress of a leader’s unexpected death and he decreed that Umar, (who was previously Muhammad’s second closest friend), would succeed him as Caliph.  Umar sent his armies out to conquer non-Muslim lands and they conquered Syria, Palestine, Iraq, Persia, and Egypt.  (Persia suffered especially under the Arab’s oppression).  These were conquests by the sword.  Wars and battles were fought but over time the Muslims conquered.  Islam was certainly not then a religion of peace, it was instead a religion of power, force, and brutality.  Tens of thousands were killed and hundreds of thousands were subjected by force to Islam’s rule.  Those that converted to Islam were treated much better than the non-Muslims, and through this oppressive bigotry Islam coerced people to convert.

UTHMAN
Uthman assumed leadership after Umar died.  Uthman’s claim to fame is that he issued the official recension of the Quran we have today.  There were many different Qurans in existence.  They were mostly similar but also had notable differences.  These differences caused severe divisions amongst the Muslims.  Uthman fixed this by having an official version of the Quran made and ordered other competing Qurans to be burned.
Uthman’s armies conquered much of Armenia, pushed further NW into Asia, and subjected Cyprus.  During his reign the Muslims had become very powerful and wealthy.
I believe that in Uthman’s death we see Islam’s truest fruit.  Political corruption set in and many Muslims became disgruntled and upset with Uthman.  Eventually large groups of these disgruntled Muslims from several Muslim regions went to Medina to confront Uthman.  One of these groups was from Egypt and they wanted Ali to assume the Caliphate.
Ali, Muhammad’s son in law, was responsible to protect the aged Uthman.  Initially he did post guards and fulfilled his responsibility. 
However, deep down Ali seethed with bitterness and resentment because he felt that he should have been made successor to Muhammad.  Instead he bit his tongue as one by one, Abu Bakr, Umar, and then Uthman, assumed the role.  His bitterness rooted itself ever deeper in his heart while he coveted the wealth, status, and power of being Caliph.
The confrontation between the disgruntled Muslim gangs and Uthman took a turn for the worse.  It was at this point Ali withdrew his family and guards responsible for protecting Uthman.  Uthman was then attacked and murdered.  Ali’s men were nowhere to be found.
It’s important to note that one of the assailants was Abu Bakr’s son, Muhammad b. Abi Bakr.  Here is Tabari’s account:
Muhammad b. Abi Bakr, came with thirteen men and went up to Uthman.  He seized his beard and shook it until I heard his teeth chattering. Muhammad b. Abi Bakr said, “Muawiyah was no help to you, nor was Ibn Amir, nor your letters.”  Uthman said, “Let go of my beard, son of my brother!  Let go of my beard!”  Then I saw Ibn Abi Bakr signaling with his eye to one of the rebels.  He came over to him with a broad iron headed arrow and stabbed him in the head with it…. They gathered round him and killed him.”6

Conversely, imagine this: Jesus’s apostles hating, fighting with, and murdering each other.  Imagine Peter’s son murdering Thomas.  It would be quite horrible; it would be a dark and evil situation.
The story actually gets worse, darker, and more evil.  After Uthman’s death there was an outcry to punish the murderers.  With the support of the Egyptian gang Ali assumed the Caliphate.  To make a long story short some prominent Muslims, Talhah, al-Zubayr, and Aisha, Muhammad’s child bride, started the first civil war in Islam.  Ali and his army marched against them and they fought.  This battle is known as “The Battle of the Camel.”  Ali was triumphant.  Talhah and al-Zubayr were killed and Aisha put under house arrest.  Casualty figures range from ten to twenty thousand killed. 
I could give many more examples of Muhammad’s “Companions” murdering other “Companions” for power or greed.  Perhaps its apex is the battle of Siffin, or perhaps its apex is when Yazid, a Muslim leader in Damascus and the grandson of Muhammad’s arch-enemy Abu Sufyan, killed Muhammad’s grandson, Husain.  Husain’s head was brought to Yazid and he and his companions desecrated it.

Better yet get Tabari’s History and read it for yourself.  Don’t let anyone do your thinking for you.  Read and study the Islamic source materials for yourself.  Start with volume 10: “The History of al-Tabari Vol. 10: The Conquest of Arabia: The Riddah Wars A.D. 632-633/A.H. 11”


CONCLUSION
This was a brief, general comparison of two kingdoms: Christ’s versus Muhammad’s.  I wanted to present just how different these men, their methods, and their fruits are.
Jesus’s rule is an internal presence that changes men’s hearts for the better.  Jesus’s kingdom is established spiritually by persuasion and conviction.  Clearly Christ’s rule transformed men’s hearts and its evidence is found in the lives of the early Christians who won over much of the Roman Empire without the sword but by their faith and love.  It continues today in the church and in the lives of dedicated Christians.  The evidence of that kingdom-rule is disciples having “love for one another."  Without that love, as demonstrated by those foolish monks, the kingdom of God is absent.    Its strength and presence has varied over time but it has been present since His time on earth.
Muhammad’s rule is an external force that changes men’s outward lives but does not have the power to transform men’s hearts towards godliness.  Once Muhammad’s personal rule was removed by his death, his companions, Islam’s leaders, proved themselves to be unchanged, carnal, and sinful.  The early Muslims hearts were selfish, bitter, and cruel.  Their lusts and desires drove them to betray and murder their friends. 
Muhammad’s kingdom was established and maintained physically primarily by the sword.  It is both a religious and geo-political kingdom.  It institutionalizes armies, taxes, familial and cultural rules, commercial laws, etc.  It has all the constructs of a governed community and his kingdom continues today in one degree or another in both Muslim’s lives and various Muslim-majority countries.  
Muhammad was ordered by Allah to fight men to bend the knee to his Islam.  This included defense against enemy attacks and offensive actions against enemies in order to force them to submit to Muhammad’s rule.  Muhammad’s message was clear:  “Accept Islam and you will be safe.”  Further, Muhammad’s kingdom was maintained by force of arms.  When various Arab tribes left Islam, for various reasons, they were attacked and forced to re-submit to Islam or die fighting.  Like spilled blood on a white sheet Muhammad’s kingdom spread throughout the world.  During the first 100 years of Islam Muhammad’s kingdom spread and grew into one of the world’s largest empires primarily through the force of arms.
I end with three quotes from Islamic sources.  The first quote concerns Iraqi Christians, who were once Christian, converted to Islam, but then left Islam to follow Christ again.  Their words sum up my argument perfectly:
Among them were many Christians who had accepted Islam, but when dissension had developed in Islam had said, “By God, our religion from which we have departed is better and more correct than that which these people follow.  Their religion does not stop them from shedding blood, terrifying the roads, and seizing properties.”  And they returned to their former religion.  Al-Khirrit met them and said to them, “Woe unto you!  Do you know the precept of Ali regarding any Christian who accepts Islam and then reverts to Christianity?  By God he will not hear anything they say, he will not consider any excuse, he will not accept any repentance, and he will not summon them to it.  His precept regarding them is immediate cutting off of the head when he gets hold of them.”7

This second quote concerns what some of Muhammad’s Companions did to an 80 year old women whose tribe had fought the Muslims:
The Muslims were initially defeated by the Fazara. The wounded Muslim leader swore vengeance. After he recovered he went out and attacked the Fazara again. One very old woman was captured. Here is the account:
"....and Umm Qirfa Fatima was taken prisoner. She was a very old woman, wife of Malik. Her daughter and Abdullah Masada were also taken. Zayd ordered Qays to kill Umm Qirfa and he killed her cruelly (Tabari, by putting a rope to her two legs and to two camels and driving them until they rent her in two.)8

This third quote shows just how Muhammad regarded those who mock him (bear this in mind when you consider the Charlie Hebdo massacre).  This involves a Muslim man who murdered his own slave because she mocked Muhammad.
Narrated Abdullah Ibn Abbas:
A blind man had a slave-mother who used to abuse the Prophet and disparage him. He forbade her but she did not stop. He rebuked her but she did not give up her habit. One night she began to slander the Prophet and abuse him. So he took a dagger, placed it on her belly, pressed it, and killed her. A child who came between her legs was smeared with the blood that was there. When the morning came, the Prophet was informed about it.
He assembled the people and said: I adjure by Allah the man who has done this action and I adjure him by my right to him that he should stand up. Jumping over the necks of the people and trembling the man stood up.
He sat before the Prophet and said: Apostle of Allah! I am her master; she used to abuse you and disparage you. I forbade her, but she did not stop, and I rebuked her, but she did not abandon her habit. I have two sons like pearls from her, and she was my companion. Last night she began to abuse and disparage you. So I took a dagger, put it on her belly and pressed it till I killed her.
Thereupon the Prophet said: Oh be witness, no retaliation is payable for her blood.9

In all three instances above we see the murder, the brutality, the cruelty, that was part of Muhammad’s Islam.  If it was good enough for Muhammad then it’s good enough for the Muslims today. 
Part of this article’s title is “Is ISIS Islamic?”  In order to arrive at a logical, conclusive answer we need to establish what constitutes “Islamic” to establish a point of reference.   We need only examine Muhammad’s words and deeds to define “Islamic” and I’ve shown that Muhammad’s Islam, real Islam, is evil, sinful, and inhumane.  I also wanted to contrast Jesus and Muhammad.  Far too often ignorant people conflate the two and equate them because both were great religious leaders.  These two men were diametrically opposed in both their teachings and actions.