Theories of the Universe
Theories of the Universe There are many theories on the topic of 'everything', but as physicists are simple folk they can only settle for one simple answer. Just one. Most theoretical physicists have believed that, ultimately, there must be just one possible universe, the physical manifestation of a set of laws so compelling that no other option would be viable. One universe. One theory. One defining way. It was a lovely idea, but increasingly it seems a fantasy. In recent years, theory and experiment are leading to the conclusion that, far from being the only option, our universe may be just one among an almost infinite array of possible worlds. It may be that ours is simply one member of a vast cosmological swarm. Several paths seem to be leading in this direction. The most notable is string theory, which is the leading contender for a so-called theory of everything. Many physicists are convinced that some version of string theory will prove to be the final description of all physical reality, unification under one mathematical umbrella of matter, force, space and time. As the name so charmingly implies, string theory proposes that, at its core, the universe is composed of minute strings. To get a sense of what this means, imagine a subatomic particle as a tiny point; now further imagine that, as you look closer, this point turns out to be a tiny closed loop, not a
Wavelength of red light
Quality of Measurement Coursework Wavelength of red light The Aim The target is to take measurements to calculate the wavelength of red laser light by using the diffraction grating formula. Therefore I will use a variety of diffraction gratings. To improve accuracy I will always do the experiment with and in absence of two lenses. With this step I hope to get closer to the real wavelength. The Set-up Equipment list: . red laser 2. two metre rulers 3. wall or projector screen 4. double slit 5. slit holder 6. variety of diffraction gratings 7. diverging lens 8. converging lens 9. two lens holders 0. graph paper 1. cello tape, blue tack 2. marker pens The light from the laser passes through the diverging lens and splits up. Afterwards the converging lens concentrates the light. This process gives a more focused and smaller dot on the wall which leads to higher accuracy. The grating causes the concentrated light to break up again. Maxima occur on the screen where the light is in phase. The dot in the centre is called central maximum or 0th order spectrum. The next dots left and right from the central maximum are called 1st order spectrum; the next ones are called 2nd order spectrum and so on. The measurements . Set up the equipment 2. Cut the graph paper into 4 stripes and glue them together to get one long stripe 3. Stick the long stripe with blue tack on
Electromagnetic spectrum facts.
Electromagnetic spectrum facts * Waves carry vibrations through a medium. * They transfer the energy locked up in the vibrations. * Waves have a measurable speed, wavelength and frequency. * Waves meeting a boundary between mediums may be reflected, refracted or absorbed - often a mixture of all three. * Waves passing through a gap may be diffracted (spread) - the spreading is only noticeable if the gap is similar to the wavelength. * Electromagnetic waves carry transverse vibrations in electrical and magnetic fields, not vibrating particles. * E-m waves don't need matter to travel through - they can travel through empty space (a vacuum). * In a vacuum, all e-m waves travel at (approximately) 300 million metres per second (3 x 108m/s) - the fastest speed in the universe. * When e-m waves travel through matter (for example, light through air or glass), they travel a bit slower than this but rarely less than half as fast as in vacuum. * Waves of different frequencies travel at different speeds in transparent matter - so a mixture of waves can be separated out by diffraction. For example, white light is split up into a mixture of colours when it goes through a prism. The electromagnetic spectrum table This table is nearly all you need to know about the e-m spectrum on one page. The electromagnetic spectrum Print or copy it out if you want a permanent
The Science of Soundwaves and Their Applications
The Science of Soundwaves and Their Applications The science of the sound wave is important in everyday life, from its use in car mufflers to the high tech office. In this paper I'm going to talk about the sound wave and describe its characteristics, show how this science was applied to muffler design, and computer design. Sound is a pressure wave that consists of tiny fluctuations in the air pressure. The amplitude in general, is the maximum change in value of a parameter during the oscillation of a wave. In amplitude, that parameter will usually be pressure. The amplitude of a sound is the loudness of the sound. In illustration, this is the distance between a peak or trough. See illustration on previous page. The frequency is defined as the number of vibrations, oscillations, or cycles in a repeating process occurring per unit time. In the context of sound, it is the number of compressions passing a fixed point of reference in one second. The resulting unit of frequency is called Hertz (Hz). Frequency is perceived as pitch. Intensity is the rate at which sound energy flows through a defined area. Since the flow of energy is power, the dimensions of sound intensity are power/area. Usually, sound intensity is measured in watts/meter2. Intensity is perceived as loudness. Interference is a synonym for superposition. Constructive interference is the amplitude of the
The Electro magnetic spectrum.
The Electro magnetic spectrum. By Steve Wyers 11cu Radio Waves Radio waves are made by various types of transmitter, depending on the wavelength. They are also given off by stars, sparks and lightning, which is why you hear interference on your radio in a thunderstorm. Radio waves are the lowest frequencies in the electromagnetic spectrum, and are used mainly for communications. Radio waves are divided into:- Long Wave, around 1~2 km in wavelength. The radio station "Atlantic 252" broadcasts here. Medium Wave, around 100m in wavelength, used by BBC Radio 5 and other "AM" stations. VHF, which stands for "Very High Frequency" and has wavelengths of around 2m. This is where you find stereo "FM" radio stations, such as "Galaxy 101" and "GWR FM". Further up the VHF band are civilian aircraft and taxis. UHF stands for "Ultra High Frequency", and has wavelengths of less than a metre. It's used for Police radio communications, military aircraft radios and television transmissions. Large doses of radio waves are believed to cause cancer, leukaemia and other disorders. Some people claim that the very low frequency field from overhead power cables near their homes has affected their health. Microwaves Microwaves are basically extremely high frequency radio waves, and are made by various types of transmitter. In a mobile phone, they're made by a transmitter chip and an antenna,
Physics Coursework Plan Investigating how the velocity of water waves depends on the depth of water Background knowledge Speed (V/ms-¹) = distance (D/m) ÷ time (T/s) Using this equation I can calculate the speed at which the water wave travels at. The deeper the water, the faster the water wave travels Aim I am going to investigate how the velocity of water waves varies on the depth of the water and will find the relationship between these two variables. Prediction/Hypothesis I believe that when the depth of the water is increases the velocity of the water waves will increase in proportion. Average speed = distance ÷ time Apparatus * Tray * Support stand * Stop watch * Ruler * Water Diagram Variables and constants The only variables of this experiment are to be: * The depth of the water * The velocity of the waves The quantites which will remain constant are: * The temperature of the liquid * The type of liquid * The height at which the tray is lowered from * The number of waves recorded * The same tray is used To ensure a fair experiment, I will record my results 3 times. This will also increase the reliabilty of my results. I will then be able to work out an average, removing any error results out of limit. Before taking any readings of the wave velocity I will measure the length and width of the tray and also see if the tray is flat on the
What affects the voltage output of a solar panel?
What affects the voltage output of a solar panel? Planning Aim The aim of the investigation is to find out how the distance between a light point source and a photovoltaic cell affects the output potential difference. Hypothesis I predict that the further the distance, the smaller the output potential distance Inverse square law for light intensity (Taken from the website - http://hyperphysics.phy-astr.gsu.edu/hbase/vision/isql.html#c1) "Inverse square law for light intensity against distance: As the distance between an observer and a light source increases, the observable brightness decreases with d-2. Light spreads out over an increasing area of space to decrease apparent brightness. (Figure 1.1) Figure 1.1 (http://www.astrosociety.org/education/publications/tnl/32/images/fig5.gif) Because, Pin is proportional to area-1 and area is proportional to distance2, therefore Pin is proportional to distance-2 (figure 1.2). This supports my prediction that the output potential difference will be much smaller when the distance between the point source and the PV cell increases. Of course, my hypothesis assumes 100% efficiency and no influence from background light and other factors that may affect the experiment in anyway. .2 Prediction of outcome (Pin ? distance-2) Apparatus list The list of apparatus to be used is: Ray box Used as the point source to emit light
Astronomy - the urge to explore space.
Astronomy Astronomy has been a very interesting subject for every generation of mankind. From ancient Greeks to the modern astronomers, everyone has tried to explore the space probably due to the urge to discover space and find everything. The urge to explore space did not start lately but this has been passed on from generations of human beings. Some civilisations expressed the deep beauty and the attraction of the shining stars and their constellations in the space above them by worshipping them; whilst others made buildings based upon constellations of stars. A few ancient buildings in the deep and dense tropical forests that have been observed by archaeologists recently caught an astronomer's eye as something other than just an old building. He noticed that the way the building was designed exactly identical to a constellation present in the sky. When studied in detail, it was discovered that the building's door and the main door were exactly the same distance as two stars of the constellation from each other when they were looked at from the naked eye. It was also found out that the building door and the main door were at an angle of 20°. Astonishingly, this is the exact angle that the same two stars of the constellation had on each other. Until the 11th century the truth about the stars was unknown and there were just a few theories of Ancient Greeks. In the 11th
Black Holes Research and Report
Contents Page number 3 What is a Black Hole? Black Hole anatomy 4 Types of Black Hole 5 Event horizon radius 6 Mass of a black hole 7 Hawking radiation 8 What happens when Black Holes Collide? Gravitational lensing 10 Einstein rings Evaluation 11 References Black Holes By doing this assignment I aim to gain a better understanding of the physics behind Black Holes What is a Black Hole? To understand a black hole, you must first have an understanding of gravity in space. Imagine yourself on a trampoline; you make an indentation in the trampoline fabric. If someone was to roll a ball past you on the trampoline, it would begin to spiral towards you, down into the indent you have made. This is very similar to the way gravity works in space and time. The 'fabric of spacetime' is an imaginary mesh running through space (see right) which can be deformed and warped by the gravity of stars and planets. This is the principle upon which black holes work. A black hole essentially is an incredibly compact body which has warped space-time enough to make any escape from the force of gravity impossible. They are thought to be at the centre of galaxies, including our own Milky Way. As the name implies, a blackhole cannot emit or reflect any light; making them practically invisible. If enough mass is concentrated into a small enough region, the curvature of
The effects of the extension of a spring on the time it takes a weight to oscillate.
The effects of the extension of a spring on the time it takes a weight to oscillate. Introduction I am investigating the relationship between the extension of the spring and the effect it has on the time it takes for the wait on the spring to oscillate. Scientific Knowledge As the spring is extended the spring stores potential kinetic energy. So the larger X is, the more energy is stored. To work out the energy we must work out the amount of work done first: Work Done = Force x Distance When the mass is released the potential energy of the spring is converted into kinetic energy of the mass which is at a maximum when it passes through the mid-point of the oscillation which is the point where the spring is not extended at all. So the work done by the spring is equal to the mass times the acceleration of the mass times the distance. This gives the energy released by the spring: Work Done = mass x acceleration x distance At the centre point Kinetic energy is equal to Potential energy. To work out the kinetic energy: K.E = 1/2 mv2 This is the energy gained by the mass after releasing it on the extended spring. So therefore: /2 mv2 = maX /2 mass x velocity2 = mass x acceleration x extension (distance) The velocity value is the velocity at the mid point which is where the mass final comes to rest after oscillating. The formula can be simplified to: v2 = 2aX Velocity