Phys-Chem Accelerated Research Project

On the other hand, waves may interfere or overlap with one another. By solving this issue, simply add the amplitude at each identical point to find the entire wave made up of another distinct wave. After the crest of one wave intersects the trough of another, the effect is called destructive interference, which results in a smaller wave. Additionally, when the wave becomes larger after the two peaks overlap, it is known as constructive interference. To demonstrate, two sine graphs of wave beside with a different wavelength and frequency overlap with each other. Though they are plotted separately, they overlap on the same axes as shown in the third figue of the image. Then, they averaged or summed to reveal the complete wave with constructive and destructive interference at the fourth figue. The final wave in the image has both large peaks in constructive interference regions and minimal peaks in destructive interference regions. Coming to the identification of waves’ types, two cornerstone aspects are the need of medium and the direction of the forward wave. For the latter, it can be classified into two directions, which is the vertical and horizontal forward wave motion. The horizontal motion consisting of the particle displacement parallel to the wave propagation path known as longitudinal wave. 50

is known as longitudinal wave. The particles oscillate back and forth between their respective equilibrium positions instead of following the wave down the path, such as sound wave and spring wave. Moreover, longitudinal waves indicate compression and rarefaction area, which is the area of high pressure and low pressure due to how close or far the particles are. Since the compressions pass from left to right, and so does the energy, so the particles were not carried along a longitude wave. On the other hand, if the particle displacement is perpendicular to the direction of the wave travel direction, it is known as the transverse wave. To clarify, the wave travels up and down, so do the molecules, while the energy is transmitted from left to right. This process creates the crest and trough, similar to the first image of a wave above. For example, ocean water, string waves, and electromagnetic waves are the waves that travel perpendicular to the path. For the former aspect, need of medium, it classifies into the waves that need and do not need medium to travel. A wave that needs a medium in order to travel is a mechanical wave that can move in both longitudinal and transverse direction, such as sound waves, spring waves, and water waves. Essentially, if the medium has high density then the wave will travel faster. On the other hand, the waves that do not need a medium to travel and can travel through the vacuum are electromagnetic waves or EM waves. 51

James Clerk Maxwell Before going deep into electromagnetic waves, James Clerk Maxwell, a Scottish physicist born June 18, 1831 and died November 4, 1879, is known for his infamous theory of electromagnetic theory and quantum theory. His work was depicted by Albert Einstein as “the most profound and the most fruitful that physics has experienced since the time of Newton.” Aside from electromagnetic radiation, Maxwell also studied light, electricity, gas, and electromagnetism. Hence, Maxwell invented electromagnetic radiation theory, which was founded by measurements of the electric and magnetic lines of force of Micheal Faraday and theory of relativity of Albert Einstein. According to Maxwell’s understanding, he defined light as a promulgating wave of magnetic and electric fields, thus anticipating the presence of electromagnetic radiation. He then considered them as integrated magnetic and electric fields transmitted as waves at the identical speed as light. In addition, his theory of electromagnetic radiation generated formulation of the quantum hypothesis of Max Plank and became the cornerstone of theory of atoms and molecule structure advancement. 52

Not only came up with scientific theories, but he also formulated a mathematical equation of associated theory called Maxwell’s equation, making it testable and fundamental to understand the concept of his theory. This indicates that mathematics is the language of science. Hence, Magnetic and electric field’s relationship is being demonstrated by Maxwell. Mostly, his equations are about electricity and magnetism, working together with the works of Coulomb, Gauss, Oersted, and Faraday, suah as Ampere law as shown below. Moreover, the knowledge of magnetic and electric fields are applied in electromagnetic waves as they are structured by both the symmetry of magnetic and electric fields. Thus, he predicted the possibility of electromagnetic waves based on the speed, wavelength and frequencies of light, and a primary hypothesis that left for other scientists to experiment on and confirm the truth. 53

Electromagnetic Waves Electromagnetic waves (EM waves) is the description and arrangement of electromagnetic spectrum, based on their different frequencies and wavelengths. In an order, Radiowave, Microwave, Infrared, visible light, Ultraviolet, X-ray, and Gamma are the electromagnetic waves arranged from lowest to highest energy. As can be seen in the image above, the frequency of the wave is gradually increasing, and since frequency is inversely proportional to wavelength, the wavelength is decreasing. Furthermore, electromagnetic waves can be distincted into two waves that both oscillate perpendicularly, creating transverse waves. One is an oscillating electric field and the other is an oscillating magnetic field, as shown in the figure on the right. The visible radiation of electromagnetic waves is the visible light with a wavelength of 54

which made us see things around us. It consists of distinctive colors that we can observe with naked eyes; red, orange, yellow, green, blue, indigo, and violet. Continuing on high energy and frequency radiations, gamma rays, X-rays, and ultraviolet rays can be both helpful and deadly to living beings, including humans. On the other hand, infrared rays, microwave rays, and radio rays are the electromagnetic waves with low frequency, but large wavelengths, which are mostly utilized in our household applications. Firstly, gamma rays, having the highest frequency and photon energy, but the least wavelengths, are emitted by the disintegration of radionuclides. It is often utilized in medical fields, such as eliminating cancer cells, however, it still needs to be handled carefully since it can also accidentally kill other somatic cells in the human body. Moreover, gamma rays from space mostly are absorbed by the thermosphere of the Earth; the remaining gamma rays that can penetrate through the thermosphere will be blocked by the mesosphere and stratosphere next. Similarly, the thermosphere also prevents X-rays, the second highest energetic electromagnetic radiation, from entering the troposphere. X-rays are frequently used in medical imaging for observing a patient’s internal organs and, even, the cosmos. 55

Nevertheless, despite its high energy enough to crack molecules, living cells can be destroyed by the use of X-ray. Thirdly, similar to the former waves, ultraviolet radiation can damage living tissue and is absorbed by skin, which can occur in daily life, such as sunburn and the light that gradually damages our eyes. Thus, this is why sunglasses and sunscreen are needed when we are going outside in the morning or when the sun is still up in the sky. On the other side, although infrared waves (IR) consist of lower frequency and energy than the first three mentioned waves, its wavelength is larger; together with microwave and radio waves arranging from short to long wavelengths. We experience infrared waves mostly everydays without knowing, however, it is invisible to human’s naked eyes, but is identified as heat instead. For instance, a heater or a radiator, a remote television, thermal imaging, and heat from the sun all involve infrared radiation or heat radiation. Hence, a human's skin can be damaged by this heating infrared waves. Next, microwaves are also one of the radiation that is in contact with us most of the time without us knowing as well. It is used in cooking, sending radar or signals, and especially telephone; this is why researchers stated that making a phone call for a long time can be dangerous for your health. By heating up food using microwaves, foods absorb high frequencies microwaves making the food’s molecules to increase their internal energy, which causes heating. 56

Furthermore, they are both electrical and magnetic energy waves flowing through space; they can extend from 1,000 MHz to 300,000 MHz. Lastly, for the lowest frequency and longest wavelength in the electromagnetic waves, radio waves are utilized for communicating and broadcasting all over the world, such as radio, television, navigation, cellular telephony, satellite transmissions, etc. Their range of wavelengths begin from 1 millimeter to as high as 100 kilometers, moreover, they can be transmitted at a range of 3 kHz to 300 GHz. Hence, the long wavelength helps radio waves to be transmitted in a long path around the earth, so most devices that need to send signals for long distances are giving out radio waves. To conclude, electromagnetic waves are transverse waves that do not need to transmit through mediums, which include gamma, x-rays, ultraviolet, visible light, infrared, microwave, and radio waves in order from largest to smallest photon energy. Also, since frequency is inversely proportional to wavelength, gamma with the highest frequency has the least wavelength while radio wave with the lowest frequency has the largest wavelength in electromagnetic waves. All electromagnetic radiation is more or less dangerous to the human body; this is caused by the high frequency of the radiation that can disturb human internal organs and body systems. So, we should be aware when exposing to those waves . 57

Photoelectric Effect Imagine a life without Einstein’s accomplishments, a horrendous world where half of our understanding has not yet been discovered. However, we have to ask ourselves why so-called theories matter. We know his quotes, we know the theory of relativity, but are that all we seize from his achievements? In 1921, Einstein was granted the Nobel Prize for his services to theoretical physics and particularly for his discovery of the law on photoelectric effects. And now the question is; what exactly are the photoelectric effects? The name may look scary, but in reality, we have been living with and utilizing this particular theory everyday. If you do not know the photoelectric effects, you must know the photoelectric cell, or photodiode. This name should be relevant to those who seek green energy and care for the environment and should be known as a component that makes up the popular solar cell. 58

Imagine a picture of beach balls lying on a pier that spreads out into the water. The dock is a metal surface, the beach balls are electrons, and the waves in the water are light waves. If the pier was rocked by a single large wave, we could assume that the momentum from the large wave would send the beach balls flying off the dock with much more kinetic energy than a single small wave. In comparison to waves of the same size hitting the dock less often, we would expect more beach balls to be bounced off the dock as waves of the same size strike the dock more frequently. 59

Classical Theory: Light has a wave-like property Predictions: The kinetic energy of emitted photoelectrons should increase with the light amplitude. The rate of electron emission, which is proportional to the measured electric current, should increase as the light frequency is increased. One of the trends of old science fiction stories was the use of solar sails for propulsion. The idea was that the sun’s photon pressure would drive the sail similarly to wind sails and propel the spacecraft and drive it forward. This particular idea has been tested and designed for modern space flight, and what was once fiction is now reality. 60

In 1887, H. Hertz conducted a fascinating experiment and found Maxwell’s wave. However, he as well found something else that would change the total understanding of light until other significant knowledge is introduced. The photoelectric effect was observed during experiments with a spark gap generator (the pre-model radio). Sparks created between two small metal spheres in a transmitter cause sparks to hop between two separate metal spheres in a receiver in these experiments. For a receiver to accurately replicate the transmitter's spark, the air difference will always have to be less than a millimeter. Hertz discovered that illuminating his spark gap system with visible or ultraviolet light increased its sensitivity. J.J. Thomson, the man who discovered electrons in 1897, revealed that the enhanced sensitivity was due to light pressure on electrons. 61

Philipp Lenard, Hertz's assistant, was the one who carried out the initial, definitive observations of the photoelectric effect. A second metal plate was placed at the opposite end of an evacuated glass tube. The tube (called protocell) was then confined in a way so that only the first metal plate, the one made of the photoemissive substance under investigation, received illumination. Lenard wired his photocell into a circuit that also included a variable power source, voltmeter, and microampmeter. Afterwards, he used light of various frequencies and intensities to illuminate the photoemissive surface. Electrons were knocked loose, and the photoemissive plate gained a slight positive charge. As this, the circuitry of the circuit attached the second plate to the first, it became positive as well, drawing the photoelectrons floating freely through the vacuum. The light energy forced electrons around the circuit that were already there. Although the photoelectric current produced by this method was weak, it could be measured using a microammeter. If the power supply is set to a low voltage, the least energetic electrons are trapped, resulting in a decrease in current through the microammeter. If the voltage is raised, more and more energetic electrons are forced out, until nothing can leave the metal surface and the microammeter reads zero. An outcome of the photoelectric effect is a measure of the maximum kinetic energy that is emitted from the electrons. 62

Leonard found out that the intensity of light has no effect on the maximum kinetic energy of the photoelectrons (the electrons that are knocked loose by the strike of light). The electrons that were ejected from a bright light had the same quantity of energy as those that were ejected from exposure to a dim light of the same frequency. In a respect of the law of conservation of energy, however, more electrons were ejected by a bright source than a dim source.[18] The experiments that were conducted led to these following significant observations: 1. As a ray of light hits a metal base, electrons are expelled from the surface. 2. To eject electrons from each metal, a certain minimum frequency of light is needed. Threshold frequency is the name, and it varies depending on the metal. 3. The kinetic energy of the ejected electrons is directly proportional to the frequency of the incident radiation and it is independent of its intensity. 4. The number of electrons ejected per second from the metal surface depends upon the intensity or brightness of incident radiation, not the wavelength.[19] In conclusion, the photoelectric effect is the ejection of electrons (photoelectrons) from the surface of a metal as light of an appropriate frequency hits it. A photon is an electromagnetic radiation particle of zero mass and a quantum of energy. As the understanding developed over time, the new idea of the photoelectric effect has come into view in the based knowledge that the frequency of incident radiation and the substance on the surface are the two variables that influence the maximum kinetic energy of photoelectrons. 63

Above the threshold, electron energy increases in a plain linear fashion as frequency increases. The energy-frequency relationship is constant for all materials and all three curves have the identical slope which is equivalent to the Planck's constant. The energy axis has a distinct intercept for each curve, implying that threshold frequency is a property of the material. It was him, the genius of all time who came up with the most popular quote in science history, “Imagination is more important than knowledge;” Albert Einstein. In the year of 1905, Einstein discovered that light behaved as if it was made up of tiny particles, with each particle's energy equal to the frequency of the electromagnetic radiation it was a component of. Quanta was the original name for the particle, which was later changed to photons. Planck's creation was a logical reflection of reality, and Einstein's brilliance rested on his knowledge of it. It led to the realization that electromagnetic radiation, which appears to be a continuous wave, is actually a current of isolated particles. 64

“In fact, it seems to me that the observations on \"black-body radiation\", photoluminescence, the production of cathode rays by ultraviolet light and other phenomena involving the emission or conversion of light can be better understood on the assumption that the energy of light is distributed discontinuously in space. According to the assumption considered here, when a light ray starting from a point is propagated, the energy is not continuously distributed over an ever increasing volume, but it consists of a finite number of energy quanta, localized in space, which move without being divided and which can be absorbed or emitted only as a whole.” Albert Einstein, 1905 As it will be introduced further in Bohr’s model, the electron emission mechanism is defined. All Atoms have orbital electrons that are located in the principle of energy level. Electrons can be excited to a higher energy level with the interactions of electromagnetic radiation in which the electrons can return to their ground state. Nevertheless, in the case that the electrons are excited above the energy level of an atom, those electrons would be able to break free which would also lead to the atom ionization.[20] 65

Red: The ejection of electrons from the metal surface cannot be ejected by low frequency light. Green: Electrons are ejected at or above the threshold frequency (minimum frequency), ν0. Blue: A higher frequency light allows the same number of electrons to be ejected, but at a greater speed. Therefore, it can be concluded that the electrons will be ejected if the frequency is equal to or greater than the threshold frequency. The ejected electrons actually travel faster as the frequency climbs above the threshold. The number of electrons ejected rises with an increase in the intensity of light above the threshold frequency, but the increase in intensity does not affect the speed of the electron. “The number of electrons ejected was proportional to the intensity (brightness) of the light.” “The higher the frequency (above threshold), the faster the electrons travel.” 66

The equation for the photoelectric effect was depicted by Einstein with a formula that correlates the photoelectrons maximum kinetic energy (Kmax) to the frequency of absorbed photons (f) and the photoemissive surface threshold frequency (f0). Where h represents Planck's constant with the value of 6.626 x 10^-34 Js. KEmax = h(f − f0) The equation can be represented in another form in corresponding to the absorbed photons energy (E) and the surface work function or metal's work function (Φ) measured in the unit of Joules. KEelectron = E − Φ The value of the metal's work function varies depending on the metal, much like the threshold frequency. Using Planck's theorem, we can now express the photon's energy in terms of light frequency: Ephoton = hν =KEelectron + Φ Rearranging equation and we get; KEelectron = hν − Φ = ( ½)mv^2 m = mass of electron 9.1094×10^−31 The maximum kinetic energy (Kmax) of the photoelectrons (with charge e) can be determined from the stopping potential (V0). 67

Therefore; Kmax = eV0 The equation that is used to measure the energy of photons of light is: E = hv E = minimum energy required to eject electrons from the metal surface. (Joules, J) ν = incoming light's frequency (Hertz, Hz) h = Planck’s constant (6.626×10^−34 J⋅s) How about the wave length? What would happen if the wavelength increased? What would happen to the photon’s energy? To answer the question, we can use the speed of light equation which is: c=λν c = the speed of light λ = wavelength ν = frequency This can be implied that the light frequency is inversely proportional to wavelength which means that the light's frequency decreases as the wavelength increases. Thus, as the wavelength of a photon increases, its energy decreases. The photoelectric effect was a phenomenon that Einstein described using light's particle nature. It proves that the particle-like activity of light. For several years, light was represented purely in terms of waves, and scientists educated in classical physics failed to recognize the wave-particle duality of light. Even if the incoming light was of low frequency, the electron in the metal might ultimately gain enough energy to be expelled from the surface if classical physics were applied to the case. 68

Alkaline Metal & Photoelectric Effects Alkali metals have original metal-like properties such as high thermal and electrical conductivity, lustre, ductility, and malleability. In the outermost shell of each alkali metal atom, there is a single electron. The valence electron in this shell is much more loosely bound than those in the inner shells. As a consequence, when alkali metals react with nonmetals, they appear to form singly charged positive ions (cations). The energy used to eject the outermost electron from an element's atoms, known as the ionization energy, decreases in the periodic table as it moves to the left and downward in each vertical group, resulting in francium being the most readily ionizable element in the table, followed by cesium. The alkali metal has a low ionization potential making it ideal for photoelectric effect. They are used in photoelectric cells because they have a low ionization energy which means that they can lose electrons fairly easily when struck.[21] 69

Spectroscopy : Interaction of Light & Matter Spectra of Stars Have you ever wondered how people in the past who travelled by voyage knew where they were in a gigantic ocean. The answer is using the north star as main navigation and other stars to support. Navigators will have a guide book about stars and binoculars as tools for determining which way they needed to go. As a background knowledge that everyone might know is the north star will be in the north of a world and the brightest star among a group of stars. The brightness of stars are caused by the concept of spectra of the stars. We know rainbow, we learned about the electromagnetic spectrum, but vw have not yet answered the most important question that is What Can Scientists Learn From a Spectrum? 70

Each element in the periodic table may exist as a gas, resulting in a sequence of bright lines that are peculiar to that element. Hydrogen will not imitate hydrogen, which will resemble carbon, which will resemble iron, and so on. As a result, astronomers can tell what sorts of things are in stars by looking at the lines in the spectrum. Spectroscopy is the name for this method of research. There is no such thing as empty space! Between the stars, there is a lot of gas and ashes. One of the most basic instruments used by physicists to research the Universe is spectroscopy and it is indeed a complicated field of research. Astronomers can calculate not only the particle, but also the temperature and density of that element in the star, using spectral lines. The spectral line will also inform us about the star's magnetic field. The line width may mean how quickly the material is going. This tells us about the winds in the stars. We will deduce that the star is orbiting another star as the lines move back and forth. This allows one to calculate the star's mass and height. We can learn about the physical changes in the star by watching the lines rise and fade in intensity. Spectral details may also disclose knowledge about the fluid that surrounds stars. 71

At first, the astronomers believed that each star had their own colors and were not all identical because of the different chemical composition or elements which produced the dark lines. However, it turned out to be wrong, actually, the stellar spectra look different because the stars have different temperatures and most stars have nearly the same formation as the Sun. For instance, the hydrogen in the hottest star and coldest star. In the atmosphere of the hottest star, the hydrogen will become ionized and absorb the photon, creating the transition. While the coldest star, all of the hydrogen atoms will remain in an unexcited state so they can only absorb photons that can move an electron from the first energy level to a higher level. In order to see the ultraviolet electromagnetic spectrum from the stars, there should be enough energy photons. As a result, you can see only very weak ultraviolet spectral lines from the coldest star. On the other hand, the astronomers will see the strong spectral lines from the hottest star.[22] The color of a star is determined by its temperature, which corresponds to its surface. The stars with the lowest temperatures are red, and the stars with the highest temperatures are blue. 72

Color measurement is just one method of measuring starlight. Another option is to scatter the light out over a continuum using a spectrograph. In 1814, German physicist Joseph Fraunhofer noticed dark lines overlapping a continuous band of colors in the Sun's spectrum. Astronomers have worked hard since then to perfect laboratory methods for collecting and analyzing spectra, as well as to establish a scientific understanding of what can be derived from spectra. Spectroscopic measurement is now considered one of the most important aspects of astronomical observation. Chemists research how various types of electromagnetic radiation interact with atoms and molecules. There are different forms of spectroscopy depending on the frequency of light we use, just as there are various types of electromagnetic radiation. The study of the absorption and emission of light and other radiation by matter is known as spectroscopy. There are various forms of electromagnetic radiation, several types of spectroscopy depend on the frequency of light we are using. Electromagnetic radiation is required in the process of splitting light into its wavelengths which was similar to how a prism separates light into a rainbow of colors. Surprisingly, spectroscopy in the old days was done with a prism and photographic plates as shown in the picture on the next page. 73

Nowadays, diffraction gratings are used in modern spectroscopy to distribute light, which is then projected onto charge-coupled devices (CCDs) like those that are used in digital cameras. The 2D spectra can be easily extracted and manipulated from this digital format to generate 1D spectra with a large amount of useful data. As a consequence, the definition of spectroscopy is expanded including the interactions between particles such as electrons, protons and ions, also their interaction with other functions as a function of their collision energy. There are 4 types of spectroscopy. First spectroscopy is astronomical, its purpose is to analyse objects in space. It will be determined by measuring the spectrum of electromagnetic radiation and its wavelength so they will allow us to know the object’s chemical composition from spectra and mass. Temperature, distance, and speed by using the function of their wavelength and speed of light. Second type is absorption spectroscopy, this type includes the use of spectroscopic techniques that can measure the absorption of radiation in matter which lead to detection of atomic makeup by testing the absorption of specific elements across the electromagnetic spectrum. Third one is biomedical spectroscopy, used in biomedical science. 74

For example, Magnetic resonance spectroscopy is often used to diagnose the chemical changes in the brain that can cause from depression to tumours. Also, analyse the metabolic structure of muscles. It works by mapping a range of wavelengths in the brain that corresponds to a known spectrum, then examining the trends and aberrations in those patterns. Fourth spectroscopy i s Energy-dispersive x-ray spectroscopy, is a technique for defining and quantifying elements present in a sample. It is used in pairs of Transmission Electron Microscopy (TEM) and Scanning Transmission Electron Microscopy (STEM) to conduct spatially elemental analysis in areas as small as few nanometers in diameter. UV-VIS SPECTROSCOPY Atoms and molecules are able to absorb energy in the forms of photons. Several phenomena could occur depending on the energy of the photon absorbed and emitted. As the atom absorbs photons of visible light or UV photons causing the excitation of atom's electrons to energy level from the increasing energy of that photon which then leads to the transition of an electron. Transition is the movement of electrons from a lower energy level to higher energy or vice versa. 75

However, to create a transition of electrons, the energy level of the absorbed photon must be greater or equal to the changes in energy between 2 energy levels. Though, there is the rise of electrons’ energy level when the electron becomes excited, it stimulates a more unstable position than it was when it was in the ground state, relaxed electrons. As a result, the electrons would easily return to the lower energy level, emitting a photon of the same energy as the difference in energy levels. As the picture shown above is the example when a hydrogen (H) atom absorbs light in the visible or the UV region of the electromagnetic spectrum. Its purpose is to help the reader to understand the energy transition, the more energy is absorbed or emitted, the larger the energy transition of atoms. For instance, when electrons fall from the fifth state to the second state, it will emit the photon of purple light whose wavelength is nearly 410 nanometer. Hence, it can be inferred that it has high in frequency, it will result in greater energy compared to the movement of electrons that fall from third state energy level to the second state that leads to the emission of red light, 700 nanometers. 76

Significantly, each of the elements are specific and unique from each other. Thus, examining the colors of light emitted by a particular atom, we can determine the elements based on their emission spectrum so it can be understood that each of their spectra is a fingerprint of an element which is the same as DNA in the living organisms. As you can see in the picture below, the wavelengths of the emission of lights can be indicated by the thin bands which are called the spectral lines. Scientists may distinguish these different wavelengths by shining light from excited atoms through a prism which will split wavelengths from each other via the process of refraction. Without the prism, we are not able to see different wavelengths of light because all of the wavelengths are blended into visible lights. However, we can find the difference wavelength by using a flame test which we used to have this type of experiment in Semester 1 in chemistry class. During that experiment, our lab technician burned copper, calcium, barium and so on that gave the colors turquoise, orange-red and pale green, respectively. In order to make those colors emitted out, we use heat energy, a type of electromagnetic radiation that is able to excite the electrons in an atom. 77

INFRARED (IR) SPECTROSCOPY : MOLECULAR VIBRATIONS Lower-energy radiation in the infrared (IR) region of the spectrum, on the other hand, can cause changes in atoms and molecules. Although this form of radiation is typically insufficiently energetic for exciting the electrons, it doesn't cause chemical bonds within molecules to vibrate in different ways. The energy needed to alter vibration of a chemical bond is constant, much like the energy required to excite an electron in a particular atom. Chemists may analyze the IR absorption spectrum of a specific molecule in the lab using special instruments, and then use that spectrum to decide what types of chemical bonds are present in the molecule. An IR spectrum, for instance, might show the composition of molecules that have carbon- carbon single bonds, carbon-carbon double bonds, and carbon-oxygen double bonds, and carbon-nitrogen single bonds. Because each of these bonds is unique, they can vibrate in various ways and absorb different wavelengths of IR radiation. 78

SPECTROPHOTOMETRY This spectroscopy is a tool for determining the concentration of colored compound solutions. Example of application of this spectroscopy is food coloring in water or the solution, in which apply to the absorption of visible light. Hence, the darker of solutions, the more intake of visible light. In order to determine the concentration of solution, the chemists will put the unknown concentration to a spectrophotometer, a device that measures the absorbance of the solution. The absorbance scale is between 0 and 1. An absorbance of zero means that light can be totally passed through the solution. For an absorbance of 1, meaning that light is not capable of passing through the solution.[23] HEISENBERG UNCERTAINTY PRINCIPLE Heisenberg Uncertainty Principle which is also known as Uncertainty principle was published by German physicist named Werner Kari Heisenberg. He published his breakthrough paper in 1925 and during that time the matrix of quantum mechanics was elaborated fundamentally. Two years later, the uncertainty principle was published and these new discoveries paid him back Nobel Prizes in Physics for the creation of quantum mechanics back. 79

This theory arose from wave-particle duality. Heisenberg’s Uncertainty Principle states that the act of calculating a particle’s variable is fraught with uncertainty. The principle, which is commonly applied to a particle’s position and momentum. It states that the more accurately the position is known the more uncertain the momentum is. In other words, it can be inferred that all of the matters in the universe are having uncertainty in all aspects. However, this theory opposed classical Newtonian physics in which states that given good enough equipment, all particle variables are observable to an arbitrary uncertainty. The Heisenberg Uncertainty Principle is a fundamental theory in quantum mechanics theory that helps or gives the explanation about why scientists are unable to calculate many quantum variables at the same time. Before the advent of quantum mechanics, it was assumed that all variables of an object could be known with absolute precision at the same time. Newtonian physics set no limits on how improved methods and techniques could minimize measurement uncertainty, so it was theoretically possible to define all knowledge with adequate care and accuracy. Heisenberg confidently suggested that this accuracy has a lower limit, making our knowledge of a particle potentially unpredictable. 80

Though a scientist knows the precise momentum of the particle, it is still impossible to know the accurate position of the particle. Moreover, it also applied to energy and time since we can’t calculate or measure the precise energy in each system in limited time. Heisenberg defined uncertainty in the products of conjugate pairs such as momentum and position, energy and time as having minimum value equal to Planck’s constant divided by 4. To make more sense, we should compare the effect of determining an electron’s location resulting from momentum to tennis ball. To measure it, the scientist set up the experiment by using light in the form of photon particles which can be measured mass and velocity. Then let the photons come into contact with the electrons and tennis ball in order to achieve a value in their position. After two objects collide with each other and if a photon collides with an electron, a portion of its energy is transferred to the electron causing a shift in relation to this value based on their mass ratio. On the other hand, the tennis ball also experienced the same effect but it will be lessened since it has a mass several orders of magnitude greater than a photon. In conclusion, this theory governs all quantum behavior and is crucial in determining spectral line widths, as the uncertainty in a system’s energy corresponds to a line width seen in regions of the light spectrum investigated in Spectroscopy[24]. 81

PARTICLE-WAVE DUALITY Physical phenomena, such as electrons or light particles that have both wavelike and particle-like properties are said to have particle-wave duality. During 1905, Albert Einstein, a German physicist was the first one who demonstrated that light, which had previously been thought to be a type of electromagnetic waves. It also could be thought of as particle-like, localized in discrete energy packets, based on experimental proof. The findings were made about the Compton effect in 1922 by American physicist named Arthur Holly Compton. His findings could be explained if light had a wave-particle duality. Louis de Brogile, French physicist then introduced that wave properties such as wavelength and frequency are also present in other discrete bits of matter that were traditionally thought of only as material particles in 1924. Later, in 1927, American physicist Clinton Davisson and Lester Germer, as well as English physicist George Paget Thomson, independently identified the wave nature of electrons. In 1928, Danish physicist Niels Bohr revealed this interpretation of the complementary relation between the wave and particle aspects of the same phenomenon which is called complementary principle.[25] 82

Feynman Diagram Paul Dirac, a British physicist, invented an equation in 1928 that merged quantum theory and special relativity to explain the behavior of an electron traveling at relativistic speeds. From here, we can draw relations between the mathematics and the physics universe. Just as the equation x^2 = 4 can have two possible solutions (x = 2 or x = −2), Dirac's equation could have two solutions as well, one for an electron with positive energy and the other for an electron with negative energy. However, classical physics (and common sense) ruled that a particle's energy would still be positive. The equation, according to Dirac, implies that for any particle, there is an antiparticle that is equivalent to the particle but has the opposite charge. For eg, there should be an \"antielectron,\" or \"positron,\" which is similar to the electron but has a positive electric charge. The discovery opened the door to the existence of antimatter galaxies and universes. [26] As matter and antimatter collide, though, they annihilate and vanish in a burst of electricity. Matter and antimatter particles are always generated in pairs, and once they collide, they annihilate one another, leaving solely pure energy behind. In the early universe, the Big Bang should have generated an equivalent quantity of matter and antimatter. 83

Nevertheless, everything we see today is almost entirely made of matter, from the tiniest life forms on Earth to the largest celestial objects. In contrast, there isn't a lot of antimatter around. Any unexplained mechanism may have interacted with the oscillating particles, allowing a small percentage of them to decay into matter. But that is yet to be known. [27] What happen when particles collide? It turns out that if you put an electron and a positron in close proximity, they don't get along. So, they annihilate. In physics, annihilation is a reaction in which a particle collides with its antiparticle and disappears, releasing energy. An electron and its antiparticle, a positron, are the most popular annihilators on Earth. Here is what happened. The lectron and the positron are zoomed towards their target. They then collide and annihilate each other and release a very great amount of energy. The electrons and the annihilate into what is called photons also known as the Z particles. They are known to be virtual force carrier particles. A charm quark and a charm antiquark emerges from the virtual carrier particles. They then move apart from each other which stretches the color force field or the gluon fields between the particles. 84

Gluons are the exchange particles, analogous to exchange the photons that give the rise to the electromagnetic force between 2 charges of particles. The quacks then move apart even further which spreads its force fields. The energy of the force fields increases which also increases the distance between the quarks. When there is enough energy in the force fields then the energy is then converted into either quarks and antiquarks. The quarks then separate completely; they will separate into color neutral particles called mesons. It is separated into D+ and D- [28]. The diagram below shows the explanation of this marvelous adventure of the particles in quantum. Virtual force carrier particles as been said above. But what is it? Particle physics is intimately tied to these four forces. Certain fundamental particles, called carrier particles, carry these forces, and all particles can be classified according to which of the four forces they feel. The four forces are gravity, electromagnetic which is what quantum physics includes, weak forces and strong forces [29]. 85

The most important characteristic among the forces is that they are all transmitted by the exchange of a carrier particle, exactly like what Yukawa had in mind for the strong nuclear force. Each carrier particle is a virtual particle—it cannot be directly observed while transmitting the force. The photon can’t be directly because this would disrupt it and alter the force.These particles could be illustrated in a diagram which will be introduced later on. Gluons were also introduced from how the particles collided. But why are those carrier particles called gluons? The Yukawa Particle and the Heisenberg Uncertainty Principle Revisited stated that the pions are exchanged but they have a substructure. As strong forces are also related to the indirectly observed but more fundamental gluons. Furthermore, all carrier particles are said to be fundamental and also said to be no substructure. They also have similarities. Which one of them is that they all have bosons. Which bosons are particles such as photons and meson that spins quantum numbers to zero or an integral number when compared to fermion. The photons are known to have no mass and have energy. By its existence og virtual photon is possible if the virtue of Heisenberg uncertainty principle and could also travel with unlimited distances; making an infinite range of electromagnetic force. Gluons are also massless, but since they act inside massive carrier particles like pions, the strong nuclear force is also short ranged. 86

In 1922, Otto Stern and Walther Gerlach experimented with silver atoms in a diverse magnetic field. Silver atoms that were electrically neutral — with their electrons' charge perfectly matching that of the protons — were necessary for the setup. The experiment's outcome amazed the two German scientists. Rather than moving in a straight line and spacing out uniformly, it seemed that the silver atoms had formed two distinct groups collaboratively, one going up and the other down. \"Spin\" was the name given to this new property. As a consequence, electrons possessed three properties: mass, charge, and spin. [30] “Nobody ever figures out what life is all about, and it doesn't matter. Explore the world. Nearly everything is really interesting if you go into it deeply enough.” ― Richard P. Feynman Have you ever thought what life is all about? Why do we live here? What are we made of? This is what science helps us to understand the world much better. Science plays a very huge role for humans to understand the Earth much better; what we are made of; what is around us. One of them is the particles. Particles are portions of matter which humans like us could not observe through our naked eyes. This also applied to what we called it quantum mechanics. If anything that is needed to be observed on a quantum scale, some difficulties may come to place. And of course, the interaction of particles need to be observed on that scale. The best way to solve this problem is a 2 dimensional diagram, as we called it, the Feynman diagram. 87

What is it? In the movie, The Martian, Mark Watney is presumed dead after a violent storm as astronauts blast off from the planet Mars. But he did survive and live on Mars. Little to know, back on Earth, NASA and a team of worldwide scientists work as much as possible to get him home [31]. NASA taking a slow action on helping Watney, he needs to do anything to keep himself survive is the extreme environment. With the small supply he had left he needed to adapt and think fast on what he had to do. Trying his best to survive in a place where humans had never lived; with no oxygen in the atmosphere. Not everyone could do this and survive in a place where they have never been before, that is why humans have a unique way in learning and adapting to new things that come into their life. Being unique is what human beings are. But sometimes we are expected to become someone we are not, it depends on how society wants to portray ourselves. Some were born to be smart yet some do not. Making them try harder even harder in doing something. Everyone has their own interest such as taste in music, favorite subjects in your high school’s life, dream jobs. 88

Some were born to be an extrovert, having a role model making them push themselves more in what they wanted to do. But on the flip side, there are the shy and introverted people where some avoid interactions with the world [32]. Humans have the right to choose what they want to be and what they want to do. Just like the way or how we learn things are different due to our differentiation. There are many ways that we could learn to explore our life; aurally, verbally, socially, logically, physically. The one we learn best from is from learning things visually. Majorities of the people around the world learn from photos, pictures, diagrams and through drawing the text into an art work. Those visual learners snap the pictures in theri heading and understand them more than text is given to them. Science and especially physics plays a very important role in letting people understand those complicated equations into a drawing or a diagram that they could visualize on. With the help of diagrams physics has seemed simple so far. For instance the chapter in electricity; the circuit, without the knowledge to draw and understand the drawing of the circuit we could not apply those understanding into their equations. 89

When discussion of quantum started to occur, a more complicated equation and understanding is needed. By not knowing anything at all about this topic, the easiest way to acknowledge it are diagrams. A Feynman diagram could help to describe how the particles interact within a few lines and arrows. Let the exploration begin. Feynman diagram is a graphical method of representing the interactions of elementary particles [33]. This diagram was named after an American theoretical physicist whose name was Richard P. Feynman, in the 1940’s and throughout the 1950’s. During the development of the theory of quantum electrodynamics the diagram was introduced to help visualize and calculate the effects of the interaction between the electron and photons in the electromagnetic. However, nowadays, Feynman diagrams are now used to illustrate all types of interactions between particles. Everything has its story behind it especially when it comes to science. Every history has its own uniqueness and so is the Feynman diagram. Richard Phillip Feynman born on May 11, 1918 in New York, US. He was an American theoretical physicist and was famous for his work on quantum electromagnetics during the World War II era. After World War II physicists wanted to develop the theory that explained electromagnetism [34] The theory called Quantum Electrodynamics (QED) attempts to calculate the probabilities of all outcomes of the particle interactions that explains why particles alike repel each other and while the opposite charges attract each other. 90

History But this theory has its hole. Firstly, by writing down the equations which meant that each equation would be keeping track of every possible particle interaction. Which this may cause some confusion and a lot of patients needed when physicists are dealing with these equations. Secondly, when equations are scattering around and numbers quantify more and more which may lead to the breakdown of the calculation which will produce infinite values for the particle interaction that was needed to be calculated. Yet Feyman solves those problems with the easiest way to understand; by drawing. In the late 1940’s Feynman came up with the diagram for simplifying long calculations in one range of physics—quantum electrodynamics, or QED, the quantum-mechanical portrayal of electromagnetic strengths. Before long the graphs gained adherents all through the areas of atomic and particle material science. But how did it become so popular? 91

It all started in 1948 in a conference in Poconos, where Feynman started to introduce his diagram to his fellow physicists which they also used in their own work [35]. For instance, one of his physicists, Freeman Dyson translated his diagram into mathematical equations to allow researchers to understand and work with. He also showed that infinite values that were caused by QED could be converted into finite values. The diagram was known worldwide; helping researchers and was also transformed into modern theoretical physics. Feynman diagrams have helped scientists and the world to understand our universe on a smaller scale visually through a diagram. 92

How to draw As it has been said, the Feynman diagram is a diagram where you draw the possible particles interactions. It's best to know its history and what it is used for, but what is the point when you do not know how to draw it and what types of lines are used; what those lines represent. When learning to understand something, it is best to learn it physically and both visually. The majority of the people tend to struggle with physics and math which are full of equations and numbers. Yet, not anymore, this diagram will help those with visual understanding and learning. Not only is it easy to draw but also making physics sounds easier. Let start off with how to draw the Feynman diagram; step by step. The materials 93 that are needed for this diagram is only a pencil or a pen and a piece of paper and no equations are needed to be memorized. Firstly, there are 2 types of lines that could be drawn in this Feynman diagram; which are straight lines and wiggly lines as seen below in figure 1. The straight lines need arrows which could show the directions of the particle interactions.

All lines that were drawn need to be connected. If there were any excess lines that needed to be connected, try to connect every line with each other as nicely as possible. Imagine that the diagram acts like a shoelace that could be seen on figure 2. The diagram needs to be read from left to right. Knowing how to draw is not enough. Everything has its meaning and its explanations. What does each line tell or what does it represent? Let's explore. Each line is known to represent those particles and those connections between each line are the interaction of the particles. But which lines represent which types of particles? The straight lines with arrows represent fermions which are matter particles. The wiggly lines illustrate the boson which are force particles. While the interactions between these particles are known as the interactions of photon; in other words, they mediate electromagnetic interactions. As it has been said that the diagram needs to be read from left to right. Thi helps to determine the interpretation of the diagram. This helps show the directions of the electrons or the electron charge going from left to right . In other words they are the positrons which are antimatter. This is shown visually in figure 3. 1. e+ is the positron 2. e- is the electron 3. The gamma or the wiggly lines is a photon 94

Applications Real Life Usage Ever since its conception a century ago, Quantum Mechanics has given way to many inventions that we may overlook as a part of our daily life. From household appliances to large scale discoveries that revolutionized other fields like the medical field, Quantum Mechanics have done much good for us. An invention that people nowadays ever leave home without, a phone, is a product of a little smart skill that we learnt through the help of many physicists who helped formulate and explain the property of electrons, which led us to being able to manipulate the electric properties of objects, and in this case, silicon, to create a semiconductor-based electronic. Without Quantum, we wouldn’t have understood the nature of electrons and mold it to our will, within restrictions of course, and this discovery also aided in creating other electrical devices, like computers and others. 9351

On a larger, more exaggerated scheme, Quantum Mechanics had led to the invention of the Magnetic Resonance Imaging, or MRI, which is a staple in the medical field used to find deadly illnesses and treat them. The technology revolves around the reversal of the spins of the electrons, which is basically the shift in energies. MRI uses magnets and radio waves in order to give insight to the insides of the human body in great detail, with a magnetic strength 60,000 times higher than our planet’s own magnetic field. As we are composed of around 65% water, the main function of the MRI which is to measure the amount of water makes things easier. The magnet is used to measure the H, or hydrogen in the H2O molecule. The Hydrogen molecule has a single positive charge in its nucleus, and it spins on its axis like the earth. In normal circumstances, the location of the spinning of the hydrogen molecule is completely random, but with MRI, the axes of the hydrogen align with the magnetic field of the MRI. This does not mean that the hydrogen proton moves, but only that the axes align with the direction of the field while spinning. An image is generated of the human body when the proton flips back to realign with the magnetic field, energy is released, and different tissues of the cell give off different amounts of energy. With a special equipment name coil, an antenna that detects the energy, they convert the energy into a legible reading via a computer to create a comprehensive image of the desired body part. 9361

An example of something so minor we would overlook and find trivial, but would be impossible to invent had no one discovered Quantum Mechanics, is a toaster, or to be more specifically the glowing hot of the heating mechanics within it. While it seems like common sense to associate heat with the red glow of a metal rod, or yellow, blue, and white if it is at a higher temperature, there is a reason as to why it happens, and it was what the physicists strived to explain. And explained, it was. It can be noted that the color of the heated objects are almost universally similar, no matter the nature of the object, which means that the factor that is related to the nature of the object is not important in determining the reason. By using the knowledge of the spectrum, and through a desperate attempt to fit the bill and explain what would be called the ‘ultraviolet catastrophe’, Max Planck concluded that an energy emitted by an ‘oscillator’ which produced a single wavelength could only be a whole number, multiple of the energy, which developed into the glowing heat rod that helps make your morning better. Without Max Planck and his constant, we would never have this delicious breakfast. These examples are just small things that show how Quantum has created the life 9371 we are used to, though of course it is not everything. Quantum is a complex interlocked web of theories that string together into various applications in various fields that help advance humanity into a different technological era in and of itself, and would continue to provide insight into the world we could become with the usage.

Solar Cell Also known as photovoltaic cell or PV cell is an electrical device that converts solar energy into electrical energy through the Photovoltaic effect. When light strikes certain semiconductor materials, the light energy is converted into electrical energy. The photovoltaic effect was introduced in 1839 by Edmond Becquerel. He discovered the effect when he was working with the wet cell. The discovery was that when the cell's silver 98 plates were exposed to sunlight, the voltage of the cell rose. To guide the understanding of the process of the photovoltaic effect, we shall imagine a block of silicon crystal. There are four \"arms\" on silicon atoms which makes them to become ideal insulators in stable environments. When a small number of five-armed atoms (with a surplus electron) are combined, when sunlight (photons) strikes the surplus electron, a negative charge is generated . After being discharged from the arm, the electrons are free to travel. Silicon with these properties becomes a good conductor. This is known as n-type (negative) semiconductor, and it is typically caused by a phosphorous film being 'doped' onto the silicon.[36]

Combining three-armed atoms that are missing one electron, hence, this results in a hole with an electron missing. A positive charge would then be carried by the semiconductor which is known as a p-type (positive) semiconductor, and it is usually obtained by doping boron into silicon. As p-type and n-type semiconductors are placed next to each other, a p-n junction is formed. As the light approaches the p-n junction, photons can quickly pass through the thin p-type layer and through the junction. The photons provide the junction with enough energy to create a collection of electron-hole pairs. The incident light causes the junction's thermal equilibrium to be broken. The free electrons in the depletion region could easily enter the n-type side of the junction.[37] Correspondingly, depletion holes will easily reach the p-type side of the junction. Once the newly formed free electrons reach the n-type side of the junction, they are unable to cross the junction due to the barrier potential. Likewise, if the newly formed holes reach the p-type side of the junction, they are no longer able to pass it and have the same barrier potential as the junction. The p-n junction would act like a small battery cell as the concentration of electrons increases on one side, the n-type side of the junction, and the concentration of holes increases on the other side, the p-type side of the junction. A voltage is defined, which is referred to as photovoltage. There would be a tiny current running through the junction if we connect a small load across it.[38] 99