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Monday, April 9, 2012

Lawatan Pelajar SMKASR Ke UTM Skudai JB sempena Festival Inovasi dan Kreativiti 2012


Mendapat Naib Johan dan Hadiah Saguhati dalam Pertandingan DC Motor.


Pertandingan membina DC Motor sedang berjalan.



Bersiap sedia untuk mengambil bahagian dalam Pertandingan Crossward puzzle Kimia.


Noora dan Faten di dalam helikopter UTM.


Di hadapan helikopter UTM.

Wednesday, February 29, 2012

SUPERCONDUCTOR

An element, inter-metallic alloy,or compound that will conduct electricity without resistance below a certain temperature. Resistance is undesirable because it produces looses in energy flowing through the material.
Once set in motion, electric current will flow forever in a close loop of superconducting material - making it the closest thing to perpetual motion in nature.Scientist refer to superconductivity as a "macroscopic quantum phenomenon".


The next great milestone in understanding how matter behaves at extreme cold temperatures occurred in 1933. German researchers Walther Meissner and Robert Ochsenfeld discovered that a superconducting material will repel a magnetic field. A magnet moving by a conductor induces currents in the conductor. This is the principle on which the electric generator operates. But, in a superconductor the induced currents exactly mirror the field that would have otherwise penetrated the superconducting material - causing the magnet to be repulsed. This phenomenon is known as strong diamagnetism and is today often referred to as the "Meissner effect". The Meissner effect is so strong that a magnet can actually be levitated over a superconductive material.


In subsequent decades other superconducting metals, alloys and compounds were discovered. In 1941 niobium-nitride was found to superconduct at 16 K. In 1953 vanadium-silicon displayed superconductive properties at 17.5 K. And, in 1962 scientists at Westinghouse developed the first commercial superconducting wire, an alloy of niobium and titanium (NbTi). High-energy, particle-accelerator electromagnets made of copper-clad niobium-titanium were then developed in the 1960s at the Rutherford-Appleton Laboratory in the UK, and were first employed in a superconducting accelerator at the Fermilab Tevatron in the US in 1987.


The first widely-accepted theoretical understanding of superconductivity was advanced in 1957 by American physicists John Bardeen, Leon Cooper, and John Schrieffer. Their Theories of Superconductivity became know as the BCS theory - derived from the first letter of each man's last name - and won them a Nobel prize in 1972. The mathematically-complex BCS theory explained superconductivity at temperatures close to absolute zero for elements and simple alloys. However, at higher temperatures and with different superconductor systems, the BCS theory has subsequently become inadequate to fully explain how superconductivity is occurring.


Another significant theoretical advancement came in 1962 when Brian D. Josephson, a graduate student at Cambridge University, predicted that electrical current would flow between 2 superconducting materials - even when they are separated by a non-superconductor or insulator. His prediction was later confirmed and won him a share of the 1973 Nobel Prize in Physics. This tunneling phenomenon is today known as the "Josephson effect" and has been applied to electronic devices such as the SQUID, an instrument capabable of detecting even the weakest magnetic fields.


The 1980's were a decade of unrivaled discovery in the field of superconductivity. In 1964 Bill Little of Stanford University had suggested the possibility of organic (carbon-based) superconductors. The first of these theoretical superconductors was successfully synthesized in 1980 by Danish researcher Klaus Bechgaard of the University of Copenhagen and 3 French team members. (TMTSF)2PF6 had to be cooled to an incredibly cold 1.2K transition temperature (known as Tc) and subjected to high pressure to superconduct. But, its mere existence proved the possibility of "designer" molecules - molecules fashioned to perform in a predictable way.



Then, in 1986, a truly breakthrough discovery was made in the field of superconductivity. Alex Müller and Georg Bednorz, researchers at the IBM Research Laboratory in Rüschlikon, Switzerland, created a brittle ceramic compound that superconducted at the highest temperature then known: 30 K. What made this discovery so remarkable was that ceramics are normally insulators. They don't conduct electricity well at all. So, researchers had not considered them as possible high-temperature superconductor candidates. The Lanthanum, Barium, Copper and Oxygen compound that Müller and Bednorz synthesized, behaved in a not-as-yet-understood way. The discovery of this first of the superconducting copper-oxides (cuprates) won the 2 men a Nobel Prize the following year. It was later found that tiny amounts of this material were actually superconducting at 58 K, due to a small amount of lead having been added as a calibration standard - making the discovery even more noteworthy.
Müller and Bednorz' discovery triggered a flurry of activity in the field of superconductivity. Researchers around the world began "cooking" up ceramics of every imaginable combination in a quest for higher and higher Tc's. In January of 1987 a research team at the University of Alabama-Huntsville substituted Yttrium for Lanthanum in the Müller and Bednorz molecule and achieved an incredible 92 K Tc. For the first time a material (today referred to as YBCO) had been found that would superconduct at temperatures warmer than liquid nitrogen - a commonly available coolant. Additional milestones have since been achieved using exotic - and often toxic - elements in the base perovskite ceramic. The current class (or "system") of ceramic superconductors with the highest transition temperatures are the mercuric-cuprates. The first synthesis of one of these compounds was achieved in 1993 at the University of Colorado and by the team of A. Schilling, M. Cantoni, J. D. Guo, and H. R. Ott of Zurich, Switzerland. The world record Tc of 138 K is now held by a thallium-doped, mercuric-cuprate comprised of the elements Mercury, Thallium, Barium, Calcium, Copper and Oxygen. The Tc of this ceramic superconductor was confirmed by Dr. Ron Goldfarb at the National Institute of Standards and Technology-Colorado in February of 1994. Under extreme pressure its Tc can be coaxed up even higher - approximately 25 to 30 degrees more at 300,000 atmospheres.

DO IT YOURSELF MAGNETIC LEVITATION

SUPERCONDUCTOR

Friday, February 17, 2012

FACTS ABOUT WAVES

Things u should know about waves..

1. Waves transfer energy without transfering the matter.
2. In transverse waves, its particles vibrate perpendicular to the wave direction.
3. Longitudinal wave's particles vibrate parallel to the wave direction.
4. The amplitude of a wave determines its energy. Higher amplitude has greater energy.
5. Damping of wave causes decrease in amplitude & energy.
6. Waves' wavefront is always pependicular to the direction of the waves.
7. Waves undergo all of these phenomena; reflection, refraction, diffraction & interference.
8. Water,light & electromagnetic waves are transverse waves.
9. Coherent waves have same frequency ,amplitude and in phase.
10.As the frequency of a wave increases its energy increases and its wavelength decreases.
11.Shorter waves with higher frequencies have shorter periods.


Facts about Light Wave

1. Light is a transverse wave
2. Light slows down, bends toward the normal and has a shorter wavelength when it enters a higher refractive index(n) or as it moves to denser medium..
3. Medium with higher refractive index has higher optical density.
4. At the critical angle a light wave will be refracted to 90 degrees.
5. Blue light has more energy,a shorter wavelength and a higher frequency than red light (remember- ROYGBIV).
6. Monochromatic light has one color, frequency & wavelength.

Facts about water waves

1. Water waves moves faster at deeper region. This change in speed causes refraction of water waves.
2. Water waves has longer wavelength at deeper region.
3. Deeper region is less dense than shallow region.
4. Water waves bended towards normal as it moves from deeper to shallow region.
5. After diffraction, water waves amplitude decrease thus its energy decrease as well.However its speed, wavelength & frequency remain constant.

Facts about sound waves

1. Sound is a longitudinal waves.
2. Sound is produced through vibration, thus compressing & stretching the surrounding air molecules.
3. Louder sound has bigger amplitude.
4. Sound with high pitch has higher frequency.
5. The sound that we hear is known as 'audio sound' that has freuency between 20-20khz.
6. Those sound below 20hz is known as infrasound. While sound with frequency beyond 20khz is known as ultrasonic.
7. Sound require medium to travel. It travels fastest in solid> liquid> gas.
8. Sound can't be heard in vacuum..Therefore..Starwars' sound effect in outer space is a myth :)

Thursday, January 19, 2012

INTERFERENCE OF WAVES

When two or more waves simultaneously and independently travel through the same medium at the same time, their effects are superpositioned. The result of that superposition is called interference. There are two types of interference: constructive and destructive.

Constructive interference occurs when the wave amplitudes reinforce each other, building a wave of even greater amplitude.




Destructive interference occurs when the wave amplitudes oppose each other, resulting in waves of reduced amplitude.

AN AERIAL VIEW OF DIFFRACTION OF SEA WAVES

Tuesday, January 17, 2012

VELOCITY FORMULA



Today we are going to discuss velocity and then the velocity formula. First of all, we are going to define what velocity is.

Definition of velocity
Velocity is similar to speed but it has direction. Let's recap what a speed is. Speed is the rate at which something is moving.

For example, a swimmer may swim at the speed of 1 meter per second but he or she swims at the velocity of 1 meter per second east. By specifying that he or she swims in the eastwardly direction, you are defining the velocity he or she swims at. So, when you measure velocity, remember to report both speed and direction, the two components of velocity.



Velocity formula



Since velocity has direction, it is referred to in Physics as a vector quantity. A vector quantity means it is directional as opposed to a scalar quantity which is what speed is. The formula of velocity used in physics is the same as the formula used for measuring average speed per direction. Let's examine how the velocity formula works.



In the diagram above, the three velocities represented are A, B, and C. A is the speed measured in the Eastward direction, B is the speed measured in the south-eastern direction and C is the speed measured in the Northeast direction. For example, velocity A is 10 m/s east, V is 20 m/s southeast and C is 15 m/s northeast.

That's it. The velocity is measured in meter per second, the same SI unit as speed. Just remember to specify direction when reporting the velocity.

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