Sir Isaac Newton was born in England in 1642. At this time England was a country in transition, the English Civil War between Parliamentarians and Royalists was beginning and witch-hunts were still ongoing. However, scientific thought and rationale was beginning to bloom. Isaac Newton is seen as one of the key players in the scientific revolution of the 17th century and here is why.





Optics

During the 17th-century people knew that if you shone white light through a prism, a rainbow (or spectrum of light) would be projected. This was thought to be because “Sunlight must be perfect”. This idea comes from the days of Aristotle and the Ancient Greeks, when such a declaration would not be questioned nor need to be proven. However, Newton devised an experiment to challenge this idea. Firstly, Newton took two prisms and directed sunlight into his first prism and directed the rainbow towards a white piece of paper. He then cut a hole in the piece of paper so only one of the colours could shine through; and directed this beam of colour into the second prism. However, when the single colour light beam shone through the second prism, it didn’t split into many colours! Newton concluded that the coloured beams making up the spectrum of colour are the building blocks of light.





Laws of motion

Newton’s three laws of motion are the foundation of classical mechanics and we can see these laws in action in our daily lives. They describe the relationship between an object and the forces that act upon it and the subsequent motion in response to these forces. Before Newton, no one had an explanation for why things moved the way they did, yet today Newton's laws are taught in high schools!





1st law of motion: Objects in motion will remain in that state of motion unless an external force acts upon them

The best way I find to think about this law is when you push your wheelie office chair, it doesn’t roll for an eternity because an external force called friction stops your chair from rolling. Friction is the resistance to motion of one object moving relative to another and is a fundamental force like gravity.









2nd law of motion: Force = mass x acceleration

This simple equation perfectly explains the behaviour of objects when the acting forces are unbalanced. Unbalanced forces cause objects to accelerate with an acceleration that is proportional to the net force and inversely proportional to the mass.





This is tricky to visualise. So to help visualise Newton’s second law, let's imagine we are food shopping:





When you go shopping it is easy to push your empty trolley around but by the end of your shop, the trolley is almost full and much harder to push. This is because the full trolley has more mass than the empty trolley and therefore requires more force to push the trolley at the same acceleration





Also, if you push an empty trolley and a full trolley with the same force, the empty trolley will move with more acceleration as it has less mass





3rd of motion: Every action has an equal and opposite reaction

This is my favourite law of motion as you can easily feel it happening and has some applications in philosophy. You probably have a desk, table or wall nearby, now push your hand against this object. The pressure you feel is the equal and opposite reaction to your pushing! A more exciting example of this is let’s say you are in space! Space is a zero-gravity environment, so if you throw and object in front of yourself, this will cause you to will move backwards with the equal acceleration to the object you threw experienced.





Gravity

Newton later applied his three laws of motion to the relationship between the Earth, Moon and Sun – a concept he called "gravity”. Gravity is one of the most important forces in the universe. It is the force by which objects are attracted to each other. Explained by the following equation:

Force = gravitational constant x (mass of object 1 x mass of object 2)

(distance between 2 objects)squared





On Earth, gravity gives weight to physical objects, and the Moon's gravity is responsible for ocean tides. So, if gravity is the force between any two objects, why are objects near me are not drawn to me?





Well that’s because the gravitational constant is an exceptionally small number (~6.67x10-11) and other forces such as friction or drag will counter the gravitational pull. Gravity starts to become very noticeable when the mass of two objects are huge, like the earth and the moon!

The law of gravitation really does show how influential Newton was to the scientific world and how revolutionary he must have been during the 17th Century! Let us know what you think of Newton’s influence! Is there anything you think should be on this list?

#science #physics #Newton #lawsofmotion #gravity #optics #colours #spectrumofcolour #SciSouls





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