ENDEAVOUR PHYSICS

Why Physics?

• Physics is a collection of knowledge about the Physical Universe or "Nature".
• We all study physics.  We do so to live, thrive and survive.
• We study our physical surroundings to be able to use things, control things, make things and explain things.
• Our knowledge of physics is often limited by experience.   Our knowledge is based on experiences that we have either had or heard about.
  (For example, most of us have experienced sunburn from UV radiation and we have also heard that nuclear radiation is dangerous.)
• To expand our knowledge of the Physical Universe we need to think scientifically and use scientific methods to gather information and test theories.

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The Physical Universe

• The Physical Universe is where we are.   It is what we exist in, live in and move about in.  
• We interact with the Physical Universe via our physical senses.
  We can use instruments such as microscopes, telescopes or electromagnetic devices to work with things that are very small, very far away or difficult to detect - but these instruments provide readouts that we can see, hear or feel.
• There may well be other things in other dimensions around us, but these are not part of our Physical Universe.   These are either supernatural or imaginary
• Our Physical Universe consists entirely and solely of Energy and Forces that exist in Space and Time.
  (Matter is in fact a condensed form of Energy.)
• Everything that happens in Nature can be explained or predicted in terms of these four essences:   

      So, what exactly are Energy, Forces, Space and Time?

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Energy and Forces

• Energy is the basic essence of the Physical Universe.     Energy is what the Universe is made of.
  There are many different forms of energy.
  Energy either exists in a stored form - or is it is in the process of being transformed or transferred
  Energy makes things happen. 
  A simple definition of Energy is that it is the capacity to do work.
• Work occurs when energy changes from a more useful form to a less useful form.
• Energy cannot be created or destroyed. 
  Energy can be stored or released.   When energy is released, it is either transformed, transferred or transmitted.

• Forces

• Forces make things move and stop things from moving. They hold things together and keep things apart.
  Forces push  or pull.    Forces attract or repel.
• The most common forces are Mechanical Forces - those that occur during contact between objects.
  These include Friction, Pressure and Tension.
• Other forces operate in Force Fields.
  Examples of these are: Gravity, Magnetic Forces and Electric Forces.
• Forces are not eternal.   They can be created and destroyed.

Space and Time

• We live and exist in Space. Space has volume. Space is what we occupy and what we move about in. It extends infinitely in all possible directions.
• Space is infinite. There is no limit to its size. If we could measure the distance to the farthest star, there would still be space beyond that.

• Time

• We also live and exist in Time.
  Our bodies have internal clocks that sense and record the passage of time.
• Everything that happens takes time. Plants take time to grow. Explosions take milliseconds. Light takes time to travel from the sun to the earth. Nothing is instantaneous. We find it almost impossible to think of time as being anything other than constant and eternal. But what is time?
• The simple definition of time is that it is something that is measured by a clock.
• All clocks are based on movement: The swinging of a pendulum. The vibration of a quartz crystal. The movement or rearrangement of subatomic particles inside a decaying radioactive material.
• Time is based on movement through space and is therefore related to space. Because of this relationship, Einstein has proposed that Space and Time can be combined into a single dimension that is called Spacetime.

• SpaceTime

• We think of both space and time as being constant and inflexible. For almost every activity and purpose in our existence, they are.
• Einstein proposed that time and space are flexible and that the only inflexible thing in our universe is the speed of light.
  His theories predict that if we could travel at very high speeds – close to the speed of light – time would slow down. This would happen more and more as we get closer to the speed of light.
• Einstein also pointed out that our mass would increase significantly as we approached the speed of light. If we could reach the speed of light, our mass would become infinite.
• So we are extremely limited in what we can do, and where we can go, by the speed of light.