Wednesday, 22 July 2009
Saturday, 11 July 2009
How does an Airplane fly?
Every day of our lives, we hear or see at least one type of aircraft sore above our heads. Most of us travel on one once a year to make a journey of over a hundred miles to another country in an hour or two on an airplane. But how can a standard 737 (which weighs roughly 50 kg per square meter) resist the force of gravity. How can it soar at 35,000 feet at a speed of 500 miles per hour. In this article I will talk about the science behind flying in heavier than air machines.
There are two factors that prevent an airplane from flying. These are weight (preventing a plane from rising) and drag (preventing it from moving forward. For an airplane to fly, these factors must be equalled out be another two which are produced by the airplane. These are lift (created by the wings and other parts) and thrust (created by the engines. The following equations below must be obeyed to take off from the ground.
- Drag < Thrust (to move forward)
- Weight < Lift (to rise)
Now let's look at each component individually.
Drag is caused by friction with the air. As an airplane flies, its body brushes against the different air molecules creating friction. This slows the plane down.
Thrust is the opposite of drag as it is used to propel a body forward. It is created using Newton's third law of motion. It states that when one force goes one way, a force of equal strength must go the other way. Hence thrust is created by huge engines pulling and pushing huge amounts of air out the back. Therefore, an equal force must go the other way.
Weight is caused by gravity. The mass of an object depends upon what it is made up of and the weight of an object is this number in kilograms multiplied by the gravitational field strength of the Earth which is roughly 9.8 N/kg. Einstein proposed General Relatity in 1915 which states that a body curves Sapce-Time and this curvature pulls bodies into the object. This is known as gravity. We counter gravity by using lift.
We generate lift by angling the the wings so that it pushes air down. Newton's third law comes in to play again here as the air is pushed down, another force must go up. IN other words, the plane rises.
Of course, Lift doesn't have to be more than weight when its cruising as the pilot will want to remain level so the the lift will be equal the weight.
So next time you are watching a plane cruise in to the sky, remember the physics behind this way of travelling that has been attempted many times for centuries that has now become a reality.
Wednesday, 1 July 2009
Time Travel: Possible or a sci-fi myth?
by Cameron Webb
Time Travel, it is very easy, infact we do every single day but only in one direction! For thousands of years scientists and philosophers have refered to time as a river that flows steadly forward year after year, but the big question on their mind was if there was a way to swim against the flow of the river, like a salmon returning to their breeding ground 
Friday, 26 June 2009
Time
Time has been the study of many physicists over the past two centuries. Einstein was the first to really understand it by saying that it was a 4 dimensional object. In this post I will write about Time Dilation and what this has to do with a theory of time travel.
As in the Google Video in the last post, up until Einstein people thought that time was the same everywhere in the universe and that everything else varied according to a velocity. Then Einstein came along and said the speed of light was always constant and that time was variable. This formed Einstein’s special theory of relativity and also explains time dilation. 
Let’s assume that there is a man who travelled at the speed of light for eternity. Let’s also assume that you have a twin brother who goes about living his ordinary life. Your brother lives for 80 years but you live on for eternity. The obvious question to ask is why? This is where time dilation comes in.
Time dilation is based around Special and General Relativity. General Relativity explains gravity. A body of some sort, in Einstein’s view, curves the Space-Time Continuum. This curvature creates the affect that we know as Gravity. Time Dilation occurs in two ways. The first is to do with General Relativity. The less affect that gravity has on you, the slower time goes by. It varies in minute amounts but it still slows down.
The second explains the brother example that I gave earlier on. It states that the faster you go, the slower time goes by. However, if an object were to travel faster than the speed of light, it would travel back in time. In the brother principle, the speed of light is in the middle where time stops. Hence, the first man never ages.
This is one of the many time travel theories. If man could create a machine that could travel faster than light, we could time travel. However, this is currently an impossibility as the laws of physics don't allow us to do this. According to Einstein Special relativity theory, when an object gains a certain amount of energy, this energy converts into mass as explained by E=mc2. 
Another way to possibly time travel would be to use wormholes. Wormholes are like a shortcut through space-time. As in the diagram on the left, space-time sort of folds in half allowing two point that would usually be very far apart to come together. It may also help you travel in time.
Look on Wikipedia for more advanced reading.
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Saturday, 23 May 2009
Particle Physics Part 2
This article follows up from my previous introductory article on Particle Physics. In this, I will write about Fermions and Bosons, expand on the information that I gave in An introduction to Particle Physics about Quarks and Leptons and I will also touch upon how Albert Einstein made significant contributions to Physics.
To begin with however, I will write about Fermions and Bosons. Physicists believe that all things are either a Fermion or a Boson. Fermions are particles that can't occupy the same space at one time which is why we can't walk through walls as we're made up of fermions.
Bosons how ever, are forces (gravity, electromagnetism etc. etc.) which can occupy the same space at one time. For instance, gravity affects everything on Earth and electromagnetism is still present in on Earth as well.
But now back to the fundamental particles. As far as we know, there are 12 fundamental particles (24 if you include anti-particles.)But it is at CERN where the Large Hadron Collider (the largest particle accelerator in the world) is trying to find some more particles. By smashing the quarks together, they may brake down into smaller particles.
This is an example of an accelerator. However, there is no point in doing this if you can't see the particles which are created. Detectors do this.
Although we can't actually see a particle, these detectors pick up on the tracks they leave behind after the collision and where they have travelled. Tiny details like these can piece together what happened during the collision.
Finally, I will end with Albert Einstein - the greatest scientist in the history of mankind. To begin with, you must know that Einstein was very religious. He believed that God had created a universe where everything had an answer. With his General Theory of Relativity, Einstein had (accidentally) created a new field of Physics, Quantum Mechanics. However, Einstein hated the Quantum Theory as it was based on probability which Einstein didn't believe in.
This led to a debate which lasted for years with Niels Bohr - another brilliant scientist who led Quantum Mechanics of that time.
Einstein's achievements include:
- Special Relativity (which states that the speed of light is always constant and that everything else depends on the speed that you are travelling.)
- General Relativity (his theory on gravity which made him a celebrity)
- The Theory of Everything (which he never completed. He was trying to discover an equation which would prove that everything was predictable (as goes with his religious belief that everything had an answer) and that Quantum Mechanics was wrong.)
- His nobel prize for his contributions to Physics and for his photoelectric effect (the idea that photons(light) could also be particles as well as waves.)
Saturday, 11 April 2009
Introduction to Particle Physics
Particle Physics is a branch of physics that studies the fundamental constitutes of matter and energy. The fundamental constitutes of our universe (as far as we know) are 12 particles that can't be broken down any further. These particles and the four fundamental forces, come together to create what we call "The Standard Model."
Before we look at the Standard Model however, I should explain in greater depth what the fundamental particles are. They consist of 6 so-called leptons and 6 so-called quarks. But to explain these, I must explain how the atom is structured.
An atom consists of a nucleus which in it has electrically charged protons and neutral neutrons. Both these sub-atomic particles are made of up and down quarks.Then there are electrons that orbit the nucleus. These leptons are tiny compared with quarks. 
Then there are the four fundamental forces. These are Gravity (one you probably already know about), Electromagnetism (which affects the electrically charged subatomic particles), Strong Force (which acts like an elastic band upon the protons and the neutrons), and Weak Force (which is responsible for radioactivity.)
The Standard Model shows the fundamental particles and which forces affect them (Look Right)
As you can see, the Weak Force affects all the particles, the Strong Force affects all the quarks and Electromagnetism affects half of the Leptons (including the Electron) and all the quarks. It is because of the strong force affecting the quarks that we have a nucleus in our atoms.
So this concludes my introduction to Particle Physics. Soon, I will be following this up with a "Particle Physics continued" post.
Friday, 10 April 2009
A Brief Bio of Niels Bohr
By Cameron Webb
He was born the son of a University professor, won the Nobel Prize in Physics, worked with Einstein and had a son who would also go on to win the Nobel Prize - his name was Niels Bohr.
In 1885, Niels Bohr was born to a professor named Christian Bohr in Copenhagen. It was his father that would go on to nourish his interest in Physics. From an early age, Bohr loved Physics. In 1909, he gained a masters degree in Physics and two years latter he earned his Ph.D. Ten years later, after becoming a professor at the Copenhagen, he was allowed to set up the Institute of Theoretical Physics with the assistance of the Danish Government. It was this and his research in "...the investigation of the structure of atoms and of the radiation emanating from them," that earned him his Nobel prize in 1922.
During his time at the Uni of Copenhagen, he became best friends with Albert Einstein. They both wanted to solve the mystery of the Universe and were constantly giving each other "problems" to solve. These became known as the "Bohr-Einstein Debates." It was these debates that led to Bohr publishing the "Copenhagen Interpretation of Quantum Mechanics," that explained things like wave functions (see my article on Parallel Universes.)
Even in the Manhattan Project (the project that developed the first atomic bomb) Einstein and Bohr were working together.
Einstein had been sent in to exile at the start of Hitler's reign. He then moved to America and told the Americans that Germany were developing an atomic bomb. It was his warning that allowed Winston Churchill to make an informed decision during the operation that prevented the Nazi's from finishing their atomic bomb and that pointed out how essential it was to develop the bomb first.
During the project both Einstein and Bohr were directly involved in the production.
As well as these incredible contributions, he also was the father of another Nobel Prize winner - Aage Niels Bohr.
If this wasn't enough, he spent the final years of his life towards research in molecular biology.
Wednesday, 8 April 2009
A Brief Bio of Sir Isaac Newton
By Saul McNally-Summers
You may have only heard of Isaac Newton when your science teacher was talking about gravity. Although this is an achievement on its own, Sir Isaac Newton contribution to Science was far greater.
He was born in 1643 in Lincolnshire. Then, after his schooling years, he was encouraged to become a farmer-however, he hated it. Afterwards however, Trinity College saw his potential and accepted him so that he could study philosophers such as Galileo. Even at university, he began to develop a mathematical theory.
Throughout his career, Sir Isaac Newton developed calculus, explained the visible spectrum, explained gravity but, probably his biggest contribution to science was his three laws of motion.
His three laws of motion were published in his book Philosophiae Naturalis Principia Mathematica. These laws stated that(in simple English:)
1. (The Law of Inertia) An object at rest or an object moving at a constant speed will stay on its current course unless affected by an external force.
2. This law basically explains how mass and acceleration are directly linked. He basically said that if the mass of an object increases its acceleration decrease and vice versa.
3. His third law is his most famous. It states that if a force goes one way, an equally powerful force must go the other - hence recoil on a gun.
I hope now you understand just what an influential man Sir Isaac Newton was in the history of mankind.
Tuesday, 7 April 2009
The Doppler Effect, Red Shift, Blue Shift and Frequency
For all most a century people have been witnessing something very strange. Ever since the Industrial revolution transport started, i.e. trains, and as soon as an object become fast enough it produced a noise, they noticed that the further away the object is the quieter the sound is, but the closer the noise the louder the sound but as soon as it moves away from us it suddenly becomes quiet again. This interested an Austrian physicist called Christen Doppler who proposed this in 1842 and named it after him, "The Doppler Effect"
What he said confirmed that the 
sound's pitch was higher than the emitted frequency when the sound source approached him, and lower than the emitted frequency when the sound source was further away from him. (Notice on the diagram how the wavelength (period) is shorter than the low frequency wavelength this shows that the high frequency graph has a higher pitch than the low frequency graph) this graph can show you what it would look like if a car drove past you, the high frequency graph would be when the car is closer to you when the low frequency graph would be when the car is further away from you.
This also can lead us to new topic which is Red Shift, Blue Shift and Frequency but both are very similar. I have mentioned some bits about frequency but there are very important bits that I have missed out which might make the Doppler Effect make more sense. Frequency has a spectrum but with most things there is a problem and in this topic there is no exceptions, the problem is light and sound.
Lets take a car as an example, the car emits light and sound these are represented by circles. This shows that the car is
stationary, 
but look at the circles when the car is moving to the right, but when an object is moving to the right there is less space between the lines than the left. This causes a frequency change, as the lines on the right are closer together causing a higher frequency when the lines on the left are further apart causing a lower frequency. 
If we look at the frequency spectrum on the right the colour is mainly red, we call this Red Shift, and if we look at the frequency spectrum on the right the colours are mainly blue, we call this Blue Shift.
So as you can see it all adds together in just one article. Hope this has helped.
By Cameron Webb
The Theory behind Parallel Universes
By Saul McNally Summers
Parallel Universes
You have probably only heard the term “parallel universe,” in Sci-Fi films such as Doctor Who and Star Trek. But what exactly is a “parallel universe” and who thought of the concept in the first place.
For centuries physicists had been working out the laws of the world (e.g. Newton’s three laws of Motion.) But in 1900, a physicist named Max Planck, found during his study of radiation some things that disagreed with these laws. This suggested to him that there were maybe other forces in the universe that operated on a lower level than the ones he already knew about.
Then, other scientists began to find that single particles could “shape-shift.” After years of study, Niels Bohr put forward the Copenhagen Interpretation of Quantum Mechanics. This stated that all things could take the form of all possible states of matter at once. The amount of possible states a quantum object could be in is called its wave function. The apparent state of an object IN all its possible states, we say is called its superposition.
Bohr also stated that when we look at a quantum object, we affect its behaviour. Therefore, when we look at an object (e.g. a photon) we make it CHOOSE what state of matter from its wave function it wants to be from its wave function! This explains why different physicists have taken different readings from the same Quantum Object as it chose what state to be.
However, another physicist disagreed with Bohr’s statement that the object chooses its state. Instead, he believed that when an object is looked upon, the world divides – in one, it chooses a state and in the other, it chooses another to accommodate both possible outcomes. This is what is known as the “Many Worlds Theory.”
One modern day example of this happening is when you are born. In one universe you are born as an attractive, clever, polite girl but in another (to accommodate both possible outcomes) you are a rebellious, unattractive female. As a last example, let’s look at Zimbabwe and America. In a parallel universe, Zimbabwe is a rich, democratized country whereas America is corrupt and poor. It’s hard to believe but if parallel universes really did exist, that is what the world would be like.
Related topics:
- Quantum Mechanics
- Many Worlds Theory
- Wavefunction
Bouancy
What is Bouyancy? In physics the term "Bouyancy" means upwards force that keeps things afloat.
Who thought up of Bouyancy? People have been aware of objects floating on water (or sinking) since before recorded history. But it was not until Archimedes of Syracuse that the theory of flotation and the buoyancy principle was discovered.
How does it work? The force (for example gravity) that is applied on the object is equal to the weight of the fluid. The two main parts that buoyancy depends on are the object's volume (boat), and the weight of the neighbouring fluid (water). But if the object heavier than the fluid it would sink for example a rock dropped into a pond, the rock mass is larger than the mass of the water, also the rocks area has to match the area of water and the area of the rock is heavier than the area of the water.
By Cameron Webb
