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In Physics, as in any subject, there are certain key concepts that educators put a lot of effort into when teaching. For test prep its common practice to drill learners on particular concepts in the hopes that the information will be memorised for life - or at the very least until exam season is over!
Most of us can bring to mind certain principles and methods from our school days that just seem to be fixed in our memories. Perhaps it’s a spelling rule such as: “I before E except after C.” And some of us, despite our general algebraic inadequacies, can tell you without blinking that 6 x 6 = 36 thanks to maths times tables. Physics is just the same.
In order to expand your skills and knowledge of physical science you need to get down to the basics of physics first.
The key concepts on which every physicist bases their physics formulas and research projects, are the building blocks of all groundbreaking discoveries.
The trick is not to focus on memorisation but to fully comprehend the basics. Once that’s done, you’re ready for greatness and perhaps even quantum physics!
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Getting to Grips With the Basics of Physics
The Four Fundamental Forces
In the natural world, everything from the smallest atom to the entire universe is governed by four fundamental forces.
These are the fundamental forces:
1. Gravity
Gravity is the weakest of these forces and can be described as attracting two bodies of matter to each other, the greater the mass of an object, the greater it’s gravitational pull.
As we all know, the earth orbits the sun and the moon orbits the earth, all thanks to various gravitational forces.
Einstein’s Theory of Relativity actually describes the laws of this phenomenon.
2. The Weak Nuclear Force
The Weak Nuclear Force makes beta decay possible.
Beta decay occurs among subatomic particles and is responsible for the radioactive decay of atoms. It’s a phenomenon in nuclear physics that allows electrons or positrons to be emitted from an atomic nucleus which transforms the original nuclide into an isobar.
The process results in unstable atoms becoming more stable as they are able to gain a more stable ration of protons and neutrons.
3. The Strong Nuclear Force
The Strong Nuclear Force binds quarks together which results in more familiar subatomic particles, such as protons and neutrons. The atomic nucleus is held together by this force which also underlies all interactions between particles containing quarks.
4. Electromagnetism
Electromagnetism is the physical interaction occurring between electrically charged particles. It’s actually the easiest force to recognise in day to day life.
You can see electromagnetism at work in any electronic device that uses a motor such as a fan or a generator. It’s electromagnetism that allows MRI scanners to scan your body!
It was the Scottish physicist, James Clerk Maxwell, that made the discovery that electricity and magnetism travel through space in waves, much the way light does.
In fact he even figured out that electromagnetic waves actually travel at the speed of light.
There is a belief among physicists that connecting these four fundamental forces is a greater underlying force but it’s existence hasn’t yet been proven.
What Is Energy in Physics?
Waves - you’ve actually heard of a lot of them ... Microwaves, radio waves ... The list goes on.
The waves that carry energy can be measured.
Think of seismographs that take seismic readings of earthquakes, they measure seismic waves. And when we talk about measuring the length of a light wave we speak about wavelength.
One of the most concrete examples of how energy is carried in waves is the ocean and its tides.
Of all the energy waves, gravitational waves seem to be the most elusive energy phenomena. In short, these waves are ripples in space and time that are generated by accelerated masses i.e. the rotation of planets.
In 1916 Albert Einstein made a prediction of gravitational waves but it was only 100 years later that the first wave was successfully detected.
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The Laws That Govern Space
We know about the planets in our solar system and starry skies beyond. We understand the sun is essentially a ball of burning gas and that dark matter exists. But beyond all of that, the bare bones of all existence is matter and energy.
In outer space matter can be found in many forms, from something as small as a particle of dust to something as expansive as a galaxy.
Energy too can take on many forms whether it be gravitational energy or dark energy.
Dark energy has in fact become a hot topic in the scientific world and it’s believed that this is the very energy that is causing the universe to expand.
Every event that takes place in this universe, from a meteor shower to a powerful supernova is a result of matter, energy and force.
So when you have matter and also energy, all you need to add is force and you have all the ingredients for a celestial event.
The Role of Measurement in Theoretical Physics
In physics the objective is to figure out how the universe functions and this leads to studying life on earth at a subatomic level and also exploring the far reaches of our galaxy and beyond.
All of these aspects of investigation rely on the same basic concepts.
Every aspect of physics studies the way that matter is able to move through space and time and the energy and force it takes for this action to take place. Everything is measured.
Physics is a never ending practice of measuring. Capturing changes in matter and then explaining how these changes took place takes very fine tuned calculating.
And obviously when measuring one cannot use the same scale to measure the distance between two planets and the temperature on the surface of the moon.
Different countries use different measuring systems. South Africa uses the metric system as do most European countries, however the UK still uses the Imperial system and the US uses a version of the Imperial system with minor differences.
You can see how confusing all of this could become when writing a science paper.
To mitigate this problem the scientific community have implemented an international system of measurement units that is known as SI units, which stands for Système Internationale d’Unités (yes, French).
This system includes baselines for each type of measurement:
- Length is expressed in metres
- Time is broken down into seconds
- Weight (mass) is designated in kilograms
- Temperature is measured on the Kelvin scale
- Electrical current is denoted in Amperes
- A Mole is a measure of substance
Of course many things weigh far less than a kilogram and for instance electrical currents don’t always begin at one ampere. In such instances scientists must make use of decimals and exponents (and that’s where your math needs to be up to scratch!).
Scientific Abbreviations
When it comes to writing an equation it would be unproductive to have to write a nanometer like this: (0.000000001) and therefore a nanometer can be expressed simply as ‘n’.
| Prefix | Abbreviation | Exponent | How many zeros? |
|---|---|---|---|
| Tera- | T | 12 | 1,000,000,000,000 |
| Giga- | G | 9 | 1,000,000,000 |
| Mega- | M | 6 | 1,000,000 |
| Kilo- | k | 3 | 1,000 |
| centi- | c | -2 | 0.01 |
| milli- | m | -3 | 0.001 |
| micro- | µ | -6 | 0.000001 |
| nano- | n | -9 | 0.000000001 |
Although prefixes aid in making complex physics formula sheets more manageable, at some point each prefix expressing a unit will have to be converted into a numerical value in order to solve the equation.
Measuring Energy and Force
It’s easy enough to measure distance, time and mass but how do you measure energy and forces?
These are the units along with their corresponding abbreviations by which energy and force are measured:
| Unit of Measure | Abbreviation | What it measures |
|---|---|---|
| Joule | J | Energy |
| Watt | W | Power |
| Pascal | Pa | Pressure |
| Newton | N | Force |
| Hertz | Hz | Frequency |
| Ohm | O | Electrical resistance |
| Volt | V | Electric potential difference |
| Coulomb | C | Electrical charge |
| Tesla | T | Magnetic flux density |
The Laws and Formulae of Physics
Newton’s Third Law:
For every action there is an equal and opposite reaction.
This law of physics has become a common turn of phrase that tends to be used when referring to the theory of karma, although this isn't really what it means.
But how many of us are as familiar with Newton’s first and second laws:
- An object at rest tends to stay at rest unless motivated to move by an external force.
- The rate of change in momentum is directly related to the force applied.
Sir Isaac Newton is regarded as the father of classical physics, having established these fundamental laws over 330 years ago.
In fact, his name has become a viral sensation on social media following the COVID-19 crisis with millions of people finding themselves in self-isolation or quarantine.
The story goes that during a similar time when there was an outbreak of the Bubonic plague in 1665, the University of Cambridge closed temporarily and Newton used this time to develop calculus and the theory of gravity!
And although these three laws may seem obvious now, at that stage there were barely any fundamental rules that governed scientists understanding of the physical world.
Relativity
Another important physics equation that has become symbolic of modern science, E=mc². We’ve all seen it somewhere along the line but how many of us actually understand Albert Einstein’s Theory of Special Relativity?
This equation is beautiful in its simplicity but it’s more complex and significant than it seems. Basically it can be divided into two truths about physics:
- The Principle of Relativity states that physical laws apply equally, in all situations.
- In a vacuum, the speed of light is constant, regardless of any motion of the light source.
The truly phenomenal thing is that these principles have been applied over and over again and remain as true today as they were the day Einstein proved his theory.
The Laws of Thermodynamics:
The Zeroth Law makes possible the notion of temperature.
- The First Law illustrates the dynamic between a system’s internal energy, added heat, and its work.
- The Second Law outlines the natural flow of heat in a closed system
- The Third Law states that any created thermodynamic process will, by its very nature, suffer heat loss, thus never achieving perfect efficiency.
The origin of these laws dates back to the 1600's and they too are just as true today as they were all those centuries ago.
This is a true feat of genius that shows how incredible the curious human mind can be.
Electrostatic Laws
There are two laws that apply to the creation of electrostatic force and fields using particles that are electrically charged.
The first law is Coulomb’s Law stating that opposites attract but like-charged objects are repelled form one another. The law also encompasses the description of the forces involved in these attractions and repulsions.
The second law is Gauss’ Law which outlines the way an electrical charge is distributed throughout the electrical field it created.
These laws, respectively, are attributed to a physicist from France named Charles Coulomb and Carl Friedrich Gauss, a mathematician from Germany.
Throughout time and all over the world physicists have been investigating the physical aspects of our universe. But whether the studies take place on a molecular or cosmic level, the same rules apply.
With this fresh understanding of some of the fundamentals of physics you can now have a clearer idea of what aspect of physics appeals to you and do some of your own investigation!
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