UNIT 1: SCIENCE AND SOCIETY
The scientific method
STEPS
1. You identify a problem
2. You suggest a hypothesis (what you think it will happen). The hypothesis usually identifies the experimental variable of a study. This part of the scientific method involves some research about the problem.
3. You design an experiment, measuring the dependent variable
4. You put in practice your experiment and observe the results.
5. You collect your data (data analysis) with graphs and tables.
6. You draw a conclusion from the data.
7. If the hypothesis was right and is proven several times, you have a theory.
In every scientific experiment you must be able to identify :
· An independent variable: it is what is being changed.
· A dependent variable: is what is being observed or measured. It is used to determine if the experimental variable is actually acting according to the hypothesis and the data collected.
· A control group: it remains constant and without change. It is used to compare it to the experimental group.
· An experimental group: it does have the experimental variable.
How to write a research project
Topic Sentence: it is an introduction that explains what you are writing about. It is written without having researched (is has no quotes) .
Details: they are examples that involve a research. You can’t give your opinion. They are used to support the writing.
Closing sentence: it is the conclusion.
SERENDIPITY:
When something is discovered by chance. It is highly important when talking about science. Serendipity needs good luck, background knowledge and curiosity.
EXAMPLES
UNIT 2: THE UNIVERSE OUR HOME
Fundamental forces in physics
There are 4 main forces in the university. They are classified depending on their relative strength.
· Gravity: it was discovered by Newton. However, he didn’t really understand it. It was Einstein, who, after making the equations discovered the theory of relativity. He found that the medium that transmits gravity is space. This means that, space, when there is no mass on it, is flat.
But once there is mass, the space curves. This is how the Sun attracts the Earth or the Earth the Moon.
Gravity act between two objects with mass and has an infinite range. It is the weakest force. Gravity can be described by this formula: F=M1 ×M2 d2 G. Its force carrier is the graviton.
· Electromagnetism: it was discovered by Maxwell in the 19th C. It only acts between electrically charged particles. It has an infinite range. Its force carrier is the photon and it explains how particles are orientated according to a magnetic field. This force can be described by the following formula: F=K Q1 Q2d2.
For example, the plasma of the Sun are gases whose particles are orientated according to the magnetic field of the Sun.
Another example is the cloud of electrons in the atoms.
· Weak force: it is a nuclear force that controls particle decay. Particle decay is the transformation of a non-stable particle into another particle. These non-stable particles are isotopes (atoms with more neutrons than protons) that, due to their instability, tend to transform in other atoms.
For example, Carbon 14. Carbon isotopes are: C 12 (6 p+, 6 n); C 13 (6p+, 7 n) and C 14 (6 p+, 8 n). This last one is unstable so it disintegrates, transforming into N 14.
The Weak force breaks the electromagnetic force that maintains neutrons together, releasing particles from the nucleus. This disintegration emits alfa, beta or gamma radiation.
· Strong force: it is a nuclear force that opposes to the electromagnetic force, because, though the electromagnetic force states that particles with the same charge must repel each other, the strong force holds together protons (by maintaining together the quarks of the sub atomic particle). This force is the strongest one and it has a short range. The force carrier of this force is the gluon.
The creation of the Solar system: The nebular theory
1. It is believed that the solar system was first a nebula of gas, ice and dust.
2. These were kept together by gravity. As the nebula shrank, gravity increased.
3. Velocity increased and the cloud of matter and gas started to spin faster and faster. The smaller the radio, the higher the velocity (momentum).
4. The mass concentrated in the centre and formed the protosun.
5. There, thermonuclear reactions took place, releasing energy:
6. Due to the velocity, dust around the protosun flattened, forming an accretion disk of dust and planetesimals.
7. These rings of dust and ice around the Sun will collide and melt (accretion) and form planets.
The string theory
In 1907 Einstein discovered the theory of relativity, finding that the medium that transmits gravity is space itself (previously explained).
A German mathematician, named Theodor Kaluza was, as Einstein, searching for a unified theory. A theory that might be able to describe all of nature's forces from one set of ideas, one set of principles, one master equation.
So he thought that he might be able to describe electromagnetism using the same elements than Einstein: space and time, warps and curves. But these elements didn’t fit in the description of electromagnetism, so he proposed that there might be one more dimension.
When he wrote down the equations describing warps and curves in a universe with four space dimensions he found the old equations and also one more equation, because there was an extra dimension.
But, where was that extra dimension? In 1926, Oskar Klein proposed that there were two types of dimensions: big, easy-to-see dimensions and tiny, curled-up dimensions.
However, when applying this theory to physics in the universe it didn’t work. For example, they couldn't get the mass of the electron to work out correctly in this theory.
That’s why they are working on a new related theory called superstring theory. This theory tries to answer the following question: what are the basic, fundamental, indivisible, uncuttable constituents making up everything in the world around us?
Thing are made of atoms, formed by protons, neutrons and electrons. These are formed by quarks. This theory suggests that inside those, there is something, a filament of energy that vibrates in different patterns and frequencies. When vibrating, it produces the different particles that make up the world around us. Depending on the frequency the particles produced are different.
This theory shows what Einstein and Kaluza were searching for: a unified theory. Because all matter and forces of nature are put together under the rubric of vibrating strings.
Instead of 4 dimensions as Kaluza suggested, this theory works in a universe that has 10 dimensions of space and one dimension of time.
Also, what this theory might explain are the 20 numbers that describe the universe, because these numbers have to do with the extra dimensions. If they were able to know how the extra dimensions are they will discover the vibrational patterns and, thus, they’ll be able to calculate those 20 numbers and explain, for the first time, the structure of the universe.