PHYSICAL SCIENCE LEARNING MODULE POINTERS TO REVIEW_2ND QUARTER.pdf
- 1. 1 Introduction Science is the body of knowledge. Everything around us can be related with science. The study of science has its branches - life sciences and physical sciences. Life sciences include biolo- gy, zoology and botany while Physical sciences has its outer branches which are the geology, as- tronomy, chemistry and physics. However, physics is more than part of physical sciences because it does not only deal with matter and energy but it also deals with other concepts like motion, heat, sound, light, electricity, magnetism and composition of atoms. Physical science covers everything that is physical, which quite covers a lot. You may begin your journey in Physical science by learning about measurements and how to do proper lab procedures. You will also be introduced to some lessons that will prepare you for standard- ized tests in science. This module offers core concepts through direct instruction and activities that will surely stimulates the student's curiosity and will let them discover the true wonder of Physical Sciences which can be applied in our daily lives even in the simplest things we performed in our daily rou- tines. Science has different fields and through this different fields you can answer the different questions circling in your minds. Then you better read and work on the following activities pre- sented in this module. Enjoy and have fun! REMINDER! Expected Skills: To do well in every module, you need to remember and do the following: 1. Read the instructions carefully before doing anything. 2. 2.Complete all the activities and worksheets. Follow instructions on how to submit them. 3. Look up the meaning words that you do not know. 4. You will frequently come across process questions as you go through different lessons. Keep a notebook where you can write and revise your answer to questions. Use also the notebook to jot down short notes, draw diagrams, and summarize what you have just read. 5. For worksheets and reports that need to be submitted, use the provided checklist. 6. Allow time for relaxation and recreation when you are mentally tired. Make a time table to schedule your study and recreation. PHYSICAL SCIENCE IN GRADE 12 Learning Module It’s time to LEARN and have FUN! SECOND QUARTER
- 2. 2 Lesson Coverage: In this lesson, you will examine those questions when you take the following topics: Lesson 1. How the Greeks knew that the Earth is Spherical Lesson 2. Astronomical Phenomena known to Astronomers before the advent of telescopes Lesson 3. Johannes Kepler’s Discoveries from Tycho Brahe’s Collection of Astronomical Data In these topics, you will learn the following: PRE-ASSESSMENT Direction: Choose the letter of the correct answer. 1. Who was the first person to propose that Earth is spherical? A. Aristotle B. Anaxagoras C. Pythagoras D. Eratosthenes 2. Who used a primitive version of a sundial, called gnomon, in systematically observing the mo- tion of the sun? A. Babylonian and Greeks B. Egyptian and Greeks C. Babylonian and Egyptian D. Babylonian and Spartan 3. An eclipse occurs when the Earth casts its shadow on the moon when the Earth is between the Sun and the Moon. A. Solar Eclipse B. Lunar Eclipse C. Half moon Eclipse D. Waning Gibbous MODULE 1 Lesson 1 Explain how the Greeks knew that the Earth is spherical Lesson 2 Cite examples of astronomical phenomena known to astronomers before the advent of telescopes Lesson 3 Explain how Brahe’s innovations and extensive collection of data in observational astronomy paved the way for Kepler’s discovery of his laws of planetary motion 4. Who argued that if the Moon and the Sun were both spherical, then perhaps, the Earth was also spherical. A. Aristotle B. Anaxagoras C. Pythagoras D. Eratosthenes 5. Who made accurate observations of the movement of celestial bodies A. Galileo B. Aristotle C. Kepler D. Tycho Brahe Lesson 1: How the Greeks knew that the Earth is Spherical Around 500 B.C., most Greeks believed that the Earth was round, not flat. It was Pythagoras and his pupils who were first to propose a spherical Earth. 500 to 430 B.C., Anaxagoras further supported Pythagoras' proposal through his observations of the shadows that the Earth cast on the Moon during a lunar eclipse. He observed that during a lu- nar eclipse, the Earth's shadow was reflected on the Moon's surface. The shadow reflected was circular. 340 B.C., Aristotle listed several arguments for a spherical Earth which included the positions of the North star, the shape of the Moon and the Sun, and the disappearance of the ships when they sail over the horizon. NorthStar The North Star was believed to be at a fixed position in the sky. However, when the Greeks trav- eled to places nearer the equator, like Egypt, they noticed that the North Star is closer to the hori- zon. The Shape of the Sun and the Moon Aristotle argued that if the Moon and the Sun were both spherical, then perhaps, the Earth was al- so spherical. DisappearingShips If the Earth was flat, then a ship traveling away from an observer should become smaller and smaller until it disappeared. However, the Greeks observed that the ship became smaller and then its hull disappeared first before the sail as if it was being enveloped by the water until it complete- ly disappeared. The Size of the Spherical Earth It was Eratosthenes who gave the most accurate size during their time. While he was working at the Library of Alexandria in Northern Egypt, he received correspondence from Syene in Southern Egypt which stated that a vertical object did not cast any shadow at noontime during the summer solstice. PHYSICAL SCIENCE FIRST WEEK
- 3. 3 But this was not the case in Alexandria where, at noon time during the summer solstice, a verti- cal object still casts a shadow. These observations could only mean that the Sun, during this time in Alexandria, was not directly overhead. Eratosthenes then determined the angle the Sun made with the vertical direction by measuring the shadow that a vertical stick cast. He found out that in Alexandria, the Sun makes an angle of 7.2° from the vertical while 0° in Syene. To explain the difference, he hypothesized that the light rays coming from the sun are parallel, and the Earth is curved. From his measurements, he computed the circumference of the Earth to be approximately 250 000 stadia (a stadium is a unit of measurement used to describe the size of a typical stadium at the time), about 40 000 kilometers. ACTIVITY 1. EXPLAIN IT! Direction. In a 1-2 paragraph essay, explain in your own words “How did the Greeks know that Earth is sphere”. Lesson 2: Astronomical Phenomena known to Astronomers before the advent of telescopes Mercury, Venus, Mars, Jupiter, and Saturn are easily seen in the sky without the aid of tele- scopes. These planets can be easily confused with stars and are only seen at specific times of the day. Even before the invention of the telescope, ancient people have already observed different astronomical phenomena. The most observable objects in the sky are the sun and moon. Babylonian and Egyptian civilizations used a primitive version of a sundial, called gnomon, in systematically observing the motion of the sun. By looking at the shadows that the gnomon casts, they were able to observe that the sun rises in the eastern part of the sky, reaches its high- est point in midday, and sets in the western part of the sky. Also, they recorded that the points where the sun rises and sets on the horizon varies over a year and these variations happen periodically. They observed that these variations are related to weather and so concluded that seasonal changes in climate happen during a course of one year. Ancient people have observed that the moon changes its path and its appearance within a peri- od of 29.5 days. They observed that the moon changes its appearance from thin semi-circular disk to full circular disk. These phases of the moon is the basis of ancient calendars. Lunar Eclipse Besides their observation in the different phases of the moon, they also noticed that there are times when the moon or part of it seemed to be covered by a shadow for a brief moment. A lunar eclipse occurs when the Earth casts its shadow on the moon when the Earth is between the Sun and the Moon.
- 4. 4 A phenomenon such as this is known as a lunar eclipse wherein the moon changes into a dark or blood red color. Solar Eclipse Aside from lunar eclipse, the occurrence of a solar eclipse was also observed. Solar eclipse occurs when the Moon is in between the Sun and the Earth and the moon partially or completely blocks out the sun. The Motion of the Stars It was also observed that the stars appear to be attached to a celestial sphere that rotates around an axis in one day. This axis intersects the celestial sphere at a point in the northern sky and is presently close to the northern star, Polaris. Also, the constellations’ positions in the night sky vary depending on the time of the year. Visibility of Planets Astronomers have discovered that Mercury, Venus, Mars, Jupiter, and Saturn are planets because they have noticed that the stars are in a fixed position with respect to each other (like how con- stellations are always grouped). But there are very bright stars that change positions periodically. These “stars” do not belong to any group of constellations in the sky. Thus, they are called "wanderers” or planetes in Greek terms. ACTIVITY 2: Direction: Draw an example of astronomical phenomena before the discovery of tele- scope. Lesson 3: Johannes Kepler’s Discoveries from Tycho Brahe’s Collection of Astro- nomical Data Tycho Brahe was a Danish astronomer and nobleman who made accurate observations of the movement of celestial bodies in an observatory built for him by King Frederick II of Denmark in 1576. He was able to invent different astronomical instruments, with the help of his assistants, and made an extensive study of the solar system. He was able to determine the position of 777 fixed stars accurately. Johannes Kepler When King Frederick II died, and the successor did not fully support Brahe’s work, he moved to Prague in 1599 where he was supported by Emperor Rudolf II and worked as an imperial mathematician. Emperor Rudolf II recommended Johannes Kepler to work for him as an assistant. Kepler was born to a poor German family and studied as a scholar at the University of Tubingen in 1589. Brahe and Kepler's Work Brahe and Kepler had an unsteady working relationship. Kepler was Brahe's assistant. However, Brahe mistrusted Kepler with his astronomical data in fear of being shadowed by his assistant. assigned to Kepler the interpretation of his observations of Mars, whose movement did not match Brahe’s calculations. Kepler was tasked to figure out what path Mars followed as it revolved
- 5. 5 It was believed by many scientists that Brahe gave this task to Kepler to keep him occupied and left Brahe to develop his laws of planetary motion. Kepler's Discoveries from Brahe's Data Kepler postulated that there must be a force from the Sun that moves the planets. He was able to conclude that this force would explain the orbit of Mars and the Earth, including all the other planets, moved fastest when it is nearest from the Sun and moved slowest when it is farthest from the Sun Eventually, Brahe decided to give all his data to Kepler hoping that he would be able to prove his Tychonic system and put together new tables of astronomical data. This table was known as Rudolphine Tables, named after the Roman emperor and was useful in determining the posi- tions of the planets for the past 1000 years and the future 1000 years. This table was the most accurate table that is known to the astronomical world. After Brahe died in 1601, Emperor Rudolf II assigned Kepler as the new imperial mathematician, and all of Brahe’s writings, instruments, and the Rudolphine tables were passed on to him. From Brahe’s data, Kepler was able to formulate his laws of planetary motion: the law of ellipses, the law of equal areas, and the law of harmonies. Kepler’s Laws of Planetary Motion The Law of Ellipses When Kepler tried to figure out Mars’ orbit, it did not fit the then-famous theory that a planet fol- lows a circular path. He then postulated that instead of a circular path, planets follow an oval or an ellipse orbit. This orbit matched his calculations and explained the “irregularities” in the movement of Mars. He was able to formulate his first law of planetary motion, the law of ellipses which describes that the actual path followed by the planets was elliptical, not circular, with the Sun at one focus of the ellipse The Law of Equal Areas The second law, which is the law of equal areas states that when an imaginary line is drawn from the center of the Sun to the center of a planet, the line will sweep out an equal area of space in equal time intervals. The law describes how fast a planet moves in its orbit. A planet moves fastest when it is nearest the Sun and slowest when it is farthest from the Sun, and still, the same area is swept out by the line in equal amounts of time. The law of harmonies, which is the third law, describes that the square of a planet’s orbital peri- od (T2) is proportional to the cube of a planet’s average distance from the Sun (R3). It states that that the ratio of the squares of the periods of two planets is equal to the ratio of the cubes of the average distances of these two planets from the Sun or where the subscript 1 indicates planet 1 and subscript 2 indicates planet 2. ACTIVITY 3: ESSAY Direction: In a 2 paragraph essay, explain “How Brahe’s innovations help Kepler in discovering “Laws of Planetary Motion”.
- 6. 6 POST-ASSESSMENT Direction: Choose the letter of the correct answer. 1. Who was the first person to propose that Earth is spherical? A. Aristotle B. Anaxagoras C. Pythagoras D. Eratosthenes 2. Who used a primitive version of a sundial, called gnomon, in systematically observing the mo- tion of the sun? A. Babylonian and Greeks B. Egyptian and Greeks C. Babylonian and Egyptian D. Babylonian and Spartan 3. An eclipse occurs when the Earth casts its shadow on the moon when the Earth is between the Sun and the Moon. A. Solar Eclipse B. Lunar Eclipse C. Halfmoon Eclipse D. Waning Gibbous 4. Who argued that if the Moon and the Sun were both spherical, then perhaps, the Earth was also spherical. A. Aristotle B. Anaxagoras C. Pythagoras D. Eratosthenes 5. Who made accurate observations of the movement of celestial bodies A. Galileo B. Aristotle C. Kepler D. Tycho Brahe Lesson Coverage: In this lesson, you will examine those questions when you take the following topics: Lesson 1. Aristotelian vs. Galilean views of motion Lesson 2. How Galileo Inferred That Objects in Vacuum Fall with Uniform Acceleration Lesson 3. Newton’s Law of Inertia vs. Galileo’s Assertion on Horizontal Motion PRE-ASSESSMENT Direction: Choose the letter of the correct answer. 1. It is an object’s change in position with respect to time. A. Motion B. Natural Motion C. Violent Motion D. Horizontal Motion 2. A combination of uniform motion in the horizontal direction and uniformly accelerated motion in the vertical direction. A. Natural Motion B. Violent Motion C. Horizontal Motion D. Projectile Motion 3. Based on Galileo’s experiment, as the inclined plane becomes, the acceleration of ball _____________________. A. The same B. Increases C. Decreases D. No changes at all. 4. The speed increases as the ball rolled down the inclined plane because of __________________. A. Motion B. Gravity C. Friction D. Air Resistance MODULE 2 Lesson 1 Compare and contrast the Aristotelian and Galilean concep- tions of vertical motion, horizontal motion, and projectile mo- tion. Lesson 2 explain how Galileo inferred that objects in vacuum fall with uniform acceleration, and that force is not neces- sary to sustain horizontal motion Lesson 3 Explain the subtle distinction between Newton’s 1st Law of Motion (or Law of Inertia) and Galileo’s assertion that force is not necessary to sustain horizontal motion PHYSICAL SCIENCE SECOND WEEK
- 7. 7 5. I t is called this tendency of materials to resist change in their state of motion as A. Motion B. Inertia C. Friction D. Resistance Lesson 1. Aristotelian vs. Galilean views of motion Aristotelian Concepts Aristotle is one of most influential Greek philosophers whose ideas were the basis for many con- cepts that time. Motion is an object’s change in position with respect to time. According to Aris- totle, motion can either be a natural motion or a violent motion. Natural Motion An object will move and will eventually return to its natural state depending on the composition that the object is made of. An object made of material similar to earth will return to earth or an object that is similar to air will return to the air. For example, a ball mostly resembles the earth so when it is thrown upward its natural tendency is to go back to Earth, its natural state or the smoke mostly resembles the air so its natural tendency is to go up the atmosphere. Violent motion An object will move if an external force such as pushing or pulling is applied to it. No motion will take place unless there is a 'mover' in contact with an object. Aristotle’s View on Projectile Motion Aristotle believed that the motion of an object is parallel to the ground until it is the object's time to fall back into the ground. An impetus will be kept by the object until such time that the initial force is forgotten, and the object returns to its natural state to stop moving and fall to the ground. Galilean Conceptions Galileo Galilei challenged the Aristotelian view of motion when he had his actual and thorough experiments. He disagreed with most of Aristotle’s claims and provided his own description of motion. Aristotle had his view on the projectile motion of an object. He believed that an object thrown at a certain angle is given an impetus—a force or energy that permits an object to move. It will continue to move in such state until the object’s impetus is lost, and the object returns to its natu- ral state, causing it to stop and fall to the ground. Galileo disproved Aristotle’s claims and believed that the motion of objects is not simply due to the composition of objects. He mentioned that motion can be described by mathematics and the changes in some physical variables such as time and distance. Using his actual and thorough ex- periments, he was able to prove that: 1. an object in uniform motion will travel a distance that is proportional to the time it will take to travel; 2. a uniformly accelerating object will travel at a speed proportional to some factor of time; and 3. an object in motion, if unimpeded, will continue to be in motion; an external force is not neces- sary to maintain the motion. Horizontal motion An object in motion, if unimpeded, will continue to be in motion, and an external force is not neces- sary to maintain the motion. If the Earth’s surface is very flat and extended infinitely, objects that are pushed will not be impeded. Thus, the objects will continue to move. This kind of motion, how- ever, is not evident in nature. For example, if a ball is pushed on an infinitely flat plane, the ball will continue to roll if unimpeded. Vertical motion In the absence of a resistance, objects would fall not depending on their weight, but in the time of fall. Also, if the object encountered a resistive force from a fluid equal or greater than its weight, it will slow down and reaches a uniform motion until it reaches the bottom and stops. For example, without any resistance, a 1-kg object will be as fast as a 10-kg object when falling because they fall with the same amount of time, given that they are released from the same height. Also, a stone dropped in the ocean will sooner or later travel at constant speed.
- 8. 8 ACTIVITY 2: REASON OUT! 1. Based on the discussion, whose view is more acceptable? Is it Aristotle or Galileo? Why? Lesson 2. How Galileo Inferred That Objects in Vacuum Fall with Uniform Acceler- ation Galileo proved with his experiments that when objects are dropped simultaneously, they will reach the ground at the same time regardless of their masses and air resistance. In another set of experiments, he discovered that objects fall with uniform acceleration Galileo was fascinated by the behavior of falling objects. He knew that falling objects increase their speed as they go down. This change in speed is acceleration. However, he did not have any equipment to measure this change, so he used inclined planes to lessen the acceleration of the moving bodies. He was then able to investigate the moving bodies carefully. On his experiment, he had observed the following: A ball rolling down an inclined plane increases its speed by the same value after every se- cond. For example, the speed of a rolling ball was found to increase by 2 m/s every second. This means that the rolling ball would have the following speeds for every given second As the inclined plane becomes steeper, the acceleration of the rolling ball increases. Projectile motion Galileo believed that a projectile is a combination of uniform motion in the horizontal direction and uniformly accelerated motion in the vertical direction. If it is not impeded, it will continue to move even without an applied force. For example, when you shoot a ball in a basketball ring, the ball does not need a force to keep it moving. ACTIVITY 1: VENN DIAGRAM Direction: Compare and contrast the ideas of Aristotle and Galileo about motions. ARISTOTLE GALILEO
- 9. 9 If the steepness of the second inclined plane is decreased, the ball would still reach the same height from the point it was released as shown in Figure B. Finally, he then removed the second inclined plane and watched the ball as shown in Figure C. He observed the ball and made his con- clusion: the ball would continue to move in a straight line with constant speed. Galileo asserted that if friction was absent, the ball would continue to move with constant velocity. It would continue its state of motion unless a push or a pull compels it to change that state. Galileo called this tendency of materials to resist change in their state of motion as inertia. His assertion was the inspiration for Newton’s 1st law of motion. They both implied that no force is needed to keep the motion of an object and the object’s inertia would keep it from changing its state of motion. ACTIVITY 4: WHAT DO YOU THINK? 1. Do you think that there is a difference between Galileo’s assertion and Newton’s Law first Law of Motion? Why or Why not? The maximum acceleration of the rolling ball was reached when the inclined plane was posi- tioned vertically as if the ball is simply falling. These observations lead Galileo to conclude that regardless of the mass of objects and air re- sistance, falling objects would always have uniform acceleration. ACTIVITY 3: EXPERIMENT TIME! Direction: Please do the experiment, Given two one peso coins, released at the same time, Coin A is dropped while Coin B is thrown horizontally coming from the same height. 1. Which one do you think would reach the ground first? Why? Lesson 3. Newton’s Law of Inertia vs. Galileo’s Assertion on Horizontal Motion Galileo Galilei was an Italian scientist who first explained the concept of inertia. He observed that when a ball rolls down an inclined plane, its speed increases; and when it rolls upwards, its speed decreases. This change in speed was due to gravity. When the ball rolled down the inclined plane, it was pulled by gravity, so its speed increased. The opposite happened when the ball rolled up the inclined plane. He then asked himself what would happen to the ball if it was rolling on a horizontal plane such as the floor. A ball rolling on the floor is not moving with or against gravity, so what would happen to its speed? Galileo thought that the ball rolling on a floor would remain moving with constant velocity if the friction between the floor and ball would be removed. Galileo tested his theory in an experiment using two inclined planes. When the ball was rolled from one inclined plane to the next, it almost reached the height from which it was released as shown in Figure A.
- 10. 10 POST-ASSESSMENT Direction: Choose the letter of the correct answer. 1. It is an object’s change in position with respect to time. A. Motion B. Natural Motion C. Violent Motion D. Horizontal Motion 2. A combination of uniform motion in the horizontal direction and uniformly accelerated mo- tion in the vertical direction. A. Natural Motion B. Violent Motion C. Horizontal Motion D. Projectile Motion 3. Based on Galileo’s experiment, as the inclined plane becomes, the acceleration of ball _____________________. A. The same B. Increases C. Decreases D. No changes at all. 4. The speed increases as the ball rolled down the inclined plane because of __________________. A. Motion B. Gravity C. Friction D. Air Resistance 5. I t is called this tendency of materials to resist change in their state of motion as A. Motion B. Inertia C. Friction D. Resistance Lesson Coverage: In this lesson, you will examine those questions when you take the following topics: Lesson 1. Light: Particle or a Wave? Lesson 2. Energy of Light PRE-ASSESSMENT Direction: Choose the letter of the correct answer. 1. Tiny stream of particles of matter emitted by a source and spreads outward in straight lines called ______________. A. Rays B. Photons C. Quanta D. Quarks 2. It is composed of of bundles of wave energy and later called _______________. A. Rays B. Photons C. Quanta D. Quarks 3. It is the bouncing of light. A. Diffusion B. Reflection C. Refraction D. Diffraction 4. A surface or object that is capable of absorbing all radiation falling on it. A. Rays B. Opaque C. Radiation D. Blackbody 5. It is produced when light strikes a smooth surface. A. Rough Reflection B. Diffuse Reflection C. Regular Reflection D. Diffraction Reflection MODULE 3 PHYSICAL SCIENCE THIRD WEEK Lesson 1 Describe how the propagation of light, reflection, and refrac- tion are explained by the wave model and the particle model of light Lesson 2 Explain how the photon concept and the fact that the energy of a photon is directly proportional to its frequency can be used to ex- plain why red light is used in photographic dark rooms,
- 11. 11 6. It is a theory that light consists of series of waves with their wave front at right angle to the path of the rays. A. Wave Theory of Light B. Corpuscular Theory of Light C. Quantum Theory of Light D. Blackbody Radiation 7. The bending of light due to a change in its speed A. Diffusion B. Reflection C. Refraction D. Diffraction 8. It is formed when light strikes a rough surface. A. Rough Reflection B. Diffuse Reflection C. Regular Reflection D. Diffraction Reflection 9. He proposed that light acts as sets of waves and sometimes as a stream (fast moving particles of energy) of particles. A. Thomas Young B. Isaac Newton C. Louis de Brogile D. Christian Huygens 10. He proposed that light consists of tiny stream particles. A. Thomas Young B. Isaac Newton C. Louis de Brogile D. Christian Huygens Lesson 1. Light: Particle or a Wave? The exact nature of visible light is a mystery that has puzzled man for centuries. Greek scientists from the ancient Pythagorean discipline postulated that every visible object emits a steady stream of particles, while Aristotle concluded that light travels in a manner similar to waves in the ocean. Even though these ideas have undergone numerous modifications and a significant degree of evolution over the past 20 centuries, the essence of the dispute established by the Greek philosophers remains to this day. Sir Isaac Newton (Corpuscular theory of light) Advocated the particle theory that light consists of tiny stream particles (corpuscles) of matter emitted by a source and spreads outward in straight lines called rays. Made a white light coming from the sun and pass through a glass prism and he was able to show that white light was actually the sum of the different colors (separated) in the rainbow. He was able to provide explanation on the reflection and bending of light as he presented in his book Opticks. Christian Huygens (Wave theory of light) Theorized that light consists of a series of waves with their wave fronts at right angles to the path of the rays. Regarded the rays of light as lines direction of waves moving outward from the light source. His idea could also explain bending and reflection of light in his book Teatise on Light. James Clerk Maxwell (Maxwell’s Equation) He further established the wave theory using his equations. He predicted that the changing elec- tric and magnetic fields could propagate through space as electromagnetic waves and that light itself is an electromagnetic waves. Heinrich Hertz Discovered the existence of Electromagnetic waves through radio waves in 1880s then Electro- magnetic waves shared common properties with light such as reflection. In the early 19th centu- ry, the last two properties of light, interference and diffraction, were observed for the first time. Since these two unusual occurrences could not be clarified and explained by the particle theory, the wave theory became more acceptable. Max Planck (Blackbody Radiation) A blackbody is a surface or object that is capable of absorbing all radiation falling on it. He pro- posed that energy comes in discrete units called quanta (word quantum means the smallest pos- sible unit) in 1900. Albert Einstein (Quantum Theory) Theorized that light is composed of bundles of wave energy (particle like property just like the billiard ball) and later called photons in 1905. Arthur Compton Made experiments showed that photons of X-rays decreased in energy when colliding with elec- trons. His idea suggested that radiation, including light, behaves like a particle. Louis de Brogile (Wave Mechanics) Extended the possibility and proposed that matter can have wave properties. Light and even matter has a dual nature. It sometimes acts as sets of waves and sometimes as a stream (fast moving particles of energy) of particles. Reflection of Light The bouncing of light is called reflection. The types of reflection produced are based on the sur- face where the light strikes. Regular Reflection is produced when light strikes a smooth surface. Light is reflected at the same angle
- 12. 12 Diffuse Reflection is formed when light strikes a rough surface. Light is reflected in many dif- ferent directions due to irregular surface. Reflection can be observed through the different images formed using different mirrors. Mirrors can be plane (flat surface), concave (curved inward), and convex (curved outward). Refraction of Light The bending of light due to a change in its speed is called refraction. The speed of light differs as it passes through a medium. Density of the medium is considered. When light passes from a less dense medium to a denser medium, light slows down and vice versa. Every medium has its specific index of refraction. It is the measure of the amount by which a material refracts light. Its best example is the mirage (refraction of light by the earth’s atmosphere). When light passes from air at one temperature to air at another temperature, it bends. The greater the change in tempera- ture, the greater the bending. Another example of refraction is the formation of rainbow. As the light strikes the liquid particles present in the clouds, these particles act as prism where lights bends and separates, then differ- ent colors will produce. White light separates into colors of red, orange, yellow, green, blue and violet. Red has the longest wavelength refracted the least. Violet has the shortest wavelength is refracted the most. Different colors of the rainbow can be obtained using a glass that forms a spectrum known as prism. ACTIVITY 1: MATCH ME Direction: Column A Column B 1. Isaac Newton a. Photons of X-rays 2. Louis de Brogile b. Wave Mechanics 3. Christian Huygens c. Corpuscular Theory 4. Arthur Compton d. Quantum Theory 5. James Clark Maxwell e. EM Waves through radio waves 6. Albert Einstein f. Blackbody Radiation 7. Heinrich Hertz g. Maxwell’s Equation 8. Max Planck h. Wave Theory
- 13. 13 ACTIVITY 2: REASON OUT! 1. If you are going to catch a fish underwater using a spear, where will you aim it? Above the image of the fish? Below the image of the fish? Or at the image of the fish? Why? 2. Draw an example application of reflection in our daily lives. LESSON 2: ENERGY OF LIGHT Newton thought that light was made of particles (corpuscles) that emanated from the light source. Light can be described as a quanta or packet of energy that behaves as if they were par- ticles. Light quanta are called photons. The photoelectric effect introduced evidence that light showed particle properties. Photons are emitted when electrons of an atom are excited. When light is shown on an atom, its electrons absorb photon which causes them to gain energy and jump to a higher level. Since an electron can only exist at certain energy levels, it can only emit photons of certain frequencies. The emitted light can be perceived as a series of colored lines called a line or atomic spectra. Each element produces a unique set of spectral line. The electromagnetic spectrum depict all of the types of light, including those that we cannot see in our own eyes. In fact, most of the light in the universe is invisible to humans. The light we can see, made up of the individual colors of the rainbow, represents only a very small portion of the electromagnetic spec- trum. It is called visi- ble light. Other types of light include radio waves, microwaves, infrared radiation, ul- traviolet rays, X-rays and gamma rays — all of which are imper- ceptible to human eyes. The relationship between energy and frequency is given by the equation E = hf, here h is 6.63 x10 -24 joules-second called as Planck's constant. A direct relationship exists; electromagnetic radiation is more energetic with a higher frequency . Why do we get easily sunburned in ultraviolet light but not in visible light? The sun is a source of the full spectrum of the ultraviolet radiation which is responsible for causing us sunburn. This UV light has higher frequency than visible light, therefore it has higher energy. Why is red light used in photographic darkrooms? Darkrooms used red lighting to allow careful control light to pass through, so that photographic paper which is light sensitive would not be- come overexposed that will result to ruining the pictures during the developing process. Red light in the visible region of the spectrum has the lowest frequency and lowest energy and therefore it does not affect the photo developing process. How do we see colors? Visible light is a small part within the spectrum that human eyes are sensitive to and can detect. It is of different frequencies and each frequency is a particular color. Objects appear in different colors because they absorb some colors and reflect or transmit the others. White objects appear white because they reflect all colors. Black objects absorb all of
- 14. 14 D. This UV light has higher frequency than visible light, therefore it has higher energy. 6. He proposed that light acts as sets of waves and sometimes as a stream (fast moving particles of energy) of particles. A. Thomas Young B. Isaac Newton C. Louis de Brogile D. Christian Huygens 7. Tiny stream of particles of matter emitted by a source and spreads outward in straight lines called ______________. A. Rays B. Photons C. Quanta D. Quarks 8. . He proposed that light consists of tiny stream particles. A. Thomas Young B. Isaac Newton C. Louis de Brogile D. Christian Huygens 9. A surface or object that is capable of absorbing all radiation falling on it. A. Rays B. Opaque C. Radiation D. Blackbody 10. It is composed of of bundles of wave energy and later called _______________. A. Rays B. Photons C. Quanta D. Quarks ACTIVITY 3: Matching Perfectly! Directions: Match the expressions in column A with those in column B by placing the letter that corresponds to the best answer on the space provided. A B ________1. Using red light in photographic dark room a. high frequency, high energy ________2. Getting sunburned in ultraviolet light b. high frequency, low energy ________3. Seeing white t-shirt as blue c. low frequency, high energy D. low frequency, lower energy ACTIVITY 4: 1. What happens to the frequency, when the wavelength increases? 2. What happens to the energy, when the frequency increases? POST-ASSESSMENT Direction: Choose the letter of the correct answer. 1. It is emitted when electrons of an atom are excited. A. Wave B. Energy C. Photons D. Frequency 2. It is produced when light strikes a smooth surface. A. Refraction B. Reflection C. Regular Reflection D. Diffuse Reflection 3. Why is red light used in photographic darkrooms? A. Darkrooms used red lighting to allow light to pass through B. Darkrooms used red lighting to allow light to scatter C. Darkrooms used red lighting to allow light to reflect back and fourth D. Darkrooms used red lighting to allow careful control light to pass through, 4. It is formed when light strikes a rough surface. A. Refraction B. Reflection C. Regular Reflection D. Diffuse Reflection 5. Why do we get easily sunburned in ultraviolet light but not in visible light? A. This UV light has higher frequency than visible light, therefore it has lower frequency. B. This UV light has lower frequency than visible light, therefore it has higher energy. C. This UV light has lower frequency than visible light, therefore it has lower energy.
- 15. 15 Lesson Coverage: In this lesson, you will examine those questions when you take the following topics: Lesson 1. Properties of Light Lesson 2. Various Light Phenomena PRE-ASSESSMENT Direction: Choose the letter of the correct answer. 1. In what year, Max Plank was able to formulate and discover the so called Plank’s constant ? A. 1900 B. 1901 C. 1902 D. 1903 2. He first showed that light, being considered as a form of EM wave. A. Max Plank B. Arthur Compton C. Albert Einstein D. Clinton Davisson 3. He articulated that both the momentum and position of the electron can not be measured exactly at the same time. A. Max Plank B. Albert Einstein C. Werner Heisenberg D. Erwin Shrodinger 4. It is separation of white light into different colors as it passes through a prism. A. Scattering B. Dispersion C. Interference D. Diffraction 5. It is the slight bending of light as it passes around the edge of an object. A. Scattering B. Dispersion C. Interference D. Diffraction MODULE 4 PHYSICAL SCIENCE FOURTH WEEK Lesson 1 Cite experimental evidence showing that electrons can behave like waves Lesson 2 Differentiate dispersion, scattering, interference, and diffraction 6. It occurs when 2 waves meet while travelling on the same medium. A. Scattering B. Dispersion C. Interference D. Diffraction 7. Why is that rain clouds appear darker? A. Water droplets become bigger and denser and it can absorb more light than scatter it. B. Water droplets become bigger and denser and it can reflect more light than scatter it C. Water droplets become lower and less denser and it can absorb more light than scatter it. D. Water droplets become lower and less denser and it can reflect more light than scatter it. 8. It is the most sensitive or dominant color that we can see of our eyes. A. Blue B. Violet C. Indigo D. All of the above 9. He. proposed that electrons and other discrete bits of matter, must also have wave properties such as wavelength and frequency. A. Max Plank B. Albert Einstein C. Werner Heisenberg D. Louis de Broglie 10. It is made of water droplets of varying sizes. A. Rain B. Cloud C. Water droplets D. Thunder storm LESSON 1: WAVE PROPERTY OF AN ELECTRON In 1900, Max Plank was able to formulate and discover the so called Plank’s constant which he in- cluded in his discovery of Plank’s radiation Law. In 1905 German physicist Albert Einstein first showed that light, being considered as a form of EM wave, can be thought as a particle and localized in packets of discrete energy. This was shown in his photoelectric effect experiment. The observations of the Compton effect in 1922 by American physicist Arthur Holly Compton could be explained only if light had a wave-particle duality. Fascinated with the idea that light as a wave can have a particle like property, in 1924, French physicist Louis de Broglie proposed that electrons and other discrete bits of matter, which until then had been conceived only as mate- rial particles, must also have wave properties such as wavelength and frequency. Later in 1927 the wave nature of electrons was experimentally established by American physi- cists Clinton Davisson and Lester Germer on their Davisson-Germer experiment.
- 16. 16 . An understanding of the complementary relation between the wave aspects and the particle aspects of the same phenomenon was announced by Danish physicist Niels Bohr in 1928. ACTIVITY 1: QUIZ IT! Direction: Choose the letter of the correct answer. 1. He was the one who formulate and discover the so called Plank’s constant. A. Lester Germer B. Max Plank C. Clinton Davisson D. Arthur Compton 2. Who was the first person to show that light as a form of EM wave? A. Max Plank B. Neils Bohr C. Albert Einstein D. Arthur Compton 3. In what year, the wave nature of electrons was experimentally established? A. 1917 B. 1927 C. 1947 D. 1967 4. He proposed that light as a wave can have a particle like property, A. Max Plank B. Lester Germer C. Louis de Broglie D. Arthur Compton 5. He proposed that wave has properties such as wavelength and frequency. A. Max Plank B. Lester Germer C. Louis de Broglie D. Arthur Compton Electron being considered as a wave created questions that gain the interest of other fellow sci- entist. Among the question that lingered on the minds of other scientists was that “if electron traveled as a wave, then where could be the precise position of the electron within the wave?” The answer to this question was given by German physicist Werner Heisenberg in 1927, in his famous Heisenberg Uncertainty Principle. He articulated that both the momentum and position of the electron can not be measured exactly at the same time. Another scientist in the name of Erwin Shrodinger derived set of equations also called wave functions for electrons as a result of de Broglie’s hypothesis and Heisenberg’s uncertainty princi- ple. He formulated the equations that would specify that the electrons confined in their orbits would set up standing waves and the probability of finding the electrons in the orbitals could be described as the electron density clouds. The greatest probability of finding an electron in an orbital is in the densest area, likewise, the lowest probability of finding an electron in in the orbital of least dense.. ACTIVITY 2: NAME IT! 1. What are some experimental evidence supports that electron has a wavelike prop- erty LESSON 2: PROPERTIES OF LIGHT Dispersion As light enters into a prism, or an object that may act as a prism, it separates into different band of colors. This sepa- ration of white light into different col- ors as it passes through a prism is called dispersion. The separated band of colors, red, orange, yellow, green, blue, indigo and violet, ranges from 400 nanometer to 700 nano meter wave- length. Dispersion occurs due to the slight difference in the refractive index of each color. A rainbow is formed after a rainshowerwhen droplets of falling water acts as a prism that separates the rays of the sun hitting the water droplets into band of different colors. Scattering of light is respon- sible for this blue-colored sky and beautiful horizon. Tiny dust particles, and atoms of oxygen and nitrogen in the at- mosphere which are far apart from each other acts as scatter- ers. They scatter sunlight in all directions .
- 17. 17 Of the band of colors of light, violet has the shortest wavelength of 400 nanometer. It is scattered the most, followed by indigo, blue, green, yellow, orange and red which is scattered the least. But our eyes is not sensitive to indigo and violet, and blue is most predominant to our sight , so we see the blue sky. In the late afternoon where the sun is in the horizon, the loner wavelength red light reaches our eyes more than the blue light which are scattered the most. Red being scattered the least is transmitted and passed through more of the atmosphere than any other color. Thus, it is the red color together with some orange that reaches our eyes in the late afternoon and we see the beautiful red-orange sunset. Clouds are made of water droplets of varying sizes. Smaller droplets scatter blue, green , and yel- low and even red color. A combination of these color results in white clouds. Rain clouds appear dark because the water droplets become bigger and denser and it can absorb more light than scatter it. It almost all colors are absorb, the resulting color is dark or even black. ACTIVITY 3: EXPERIMENT TIME! Materials: Liquid soap, water, basin Procedure: Put some water in a basin and pour a good amount of liquid soap. Stir and make soap suds. Blow on soap suds. Observe. After doing the experiment, write what you observe in the soap bubbles. Do they produce colors or not? Interference of light The beautiful spectrum of colors reflected on the soap bubbles are produced by the interference of light. It occurs when 2 waves meet while travelling on the same medium. It may be constructive interfer- ence producing bright fringes or destruc- tive interference producing dark bands. In the case of soap bubbles, the incident ray of white light constructively interfere in the different regions of the bubbles producing the rainbow-colored appearance. Interfer- ence of light clearly demonstrates the wave nature of light . Diffraction is the slight bending of light as it passes around the edge of an object. The amount of bending depends on the relative size of the wavelength of light to the size of the opening. If the opening is much larger than the light's wavelength, the bending will be almost unnoticeable. However, if the two are closer in size or equal, the amount of bending is considerable, and easily seen with the naked eye. ACTIVITY 4: COMPARE ME Direction: Differentiate dispersion, scattering, interference and diffusion of light. Also, present an example in each properties of light. DISPERSION SCATTERING INTERFERENCE DIFFUSION
- 18. 18 POST-ASSESSMENT Direction: Choose the letter of the correct answer. 1. It occurs when 2 waves meet while travelling on the same medium. A. Scattering B. Dispersion C. Interference D. Diffraction 2. Why is that rain clouds appear darker? A. Water droplets become bigger and denser and it can absorb more light than scatter it. B. Water droplets become bigger and denser and it can reflect more light than scatter it C. Water droplets become lower and less denser and it can absorb more light than scatter it. D. Water droplets become lower and less denser and it can reflect more light than scatter it. 3. It is the most sensitive or dominant color that we can see of our eyes. A. Blue B. Violet C. Indigo D. All of the above 4. He. proposed that electrons and other discrete bits of matter, must also have wave properties such as wavelength and frequency. A. Max Plank B. Albert Einstein C. Werner Heisenberg D. Louis de Broglie 5. It is made of water droplets of varying sizes. A. Rain B. Cloud C. Water droplets D. Thunder storm 6. In what year, Max Plank was able to formulate and discover the so called Plank’s constant ? A. 1900 B. 1901 C. 1902 D. 1903 7. He first showed that light, being considered as a form of EM wave. A. Max Plank B. Arthur Compton C. Albert Einstein D. Clinton Davisson 8. He articulated that both the momentum and position of the electron can not be measured ex- actly at the same time. A. Max Plank B. Albert Einstein C. Werner Heisenberg D. Erwin Shrodinger 9. It is separation of white light into different colors as it passes through a prism. A. Scattering B. Dispersion C. Interference D. Diffraction 10. It is the slight bending of light as it passes around the edge of an object. A. Scattering B. Dispersion C. Interference D. Diffraction
- 19. 19 SECOND QUARTER EXAM IN PHYSICAL SCIENCE General Direction: This is 40 items test, read each directions written in every type of test. Multiple Choice Direction: Choose the letter of the correct answer. 1.He was the first person to propose that Earth is spherical? A. Aristotle B. Anaxagoras C. Pythagoras D. Eratosthenes 2. Who argued that if the Moon and the Sun were both spherical, then perhaps, the Earth was also spherical. A. Aristotle B. Anaxagoras C. Pythagoras D. Eratosthenes 3. Who gave the most accurate size of the spherical Earth? A. Aristotle B. Anaxagoras C. Pythagoras D. Eratosthenes 4. It occurs when the Moon is in between the Sun and the Earth. A. Solar Eclipse B. Lunar Eclipse C. Partial Eclipse D. Total Lunar Eclipse 5. It occurs when the Earth casts its shadow on the moon when the Earth is between the Sun and the Moon. A. Solar Eclipse B. Lunar Eclipse C. Partial Eclipse D.Total Lunar Eclipse 6. It is a primitive version of a sundial clock. A. Nomon B. Gnomon C. Gnomoon D. Gnoomoon 7. It describes that the actual path followed by the planets was elliptical, not circular, with the Sun at one focus of the ellipse. A. Law of Motion B. Law of Equal Areas C. Law of Harmonies D. Law of Ellipses 8. Based on Galileo’s experiment, as the inclined plane becomes steeper, the acceleration of ball _____________________. A. The same B. Increases C. Decreases D. No changes at all. 9. Combination of uniform motion in the horizontal direction and uniformly accelerated motion in the vertical direction. A. Natural Motion B. Violent Motion C. Horizontal Motion D. Projectile Motion 10. It is an object’s change in position with respect to time. A. Motion B. Natural Motion C. Violent Motion D. Horizontal Motion 11. It is the bouncing of light. A. Diffusion B. Reflection C. Refraction D. Diffraction 12. Tiny stream of particles of matter emitted by a source and spreads outward in straight lines called ______________. A. Rays B. Photons C. Quanta D. Quarks 13. A surface or object that is capable of absorbing all radiation falling on it. A. Rays B. Opaque C. Radiation D. Blackbody 14. It is emitted when electrons of an atom are excited. A. Wave B. Energy C. Photons D. Frequency 15. . It is separation of white light into different colors as it passes through a prism. A. Scattering B. Dispersion C. Interference D. Diffraction
- 20. 20 16. It is the slight bending of light as it passes around the edge of an object. A. Scattering B. Dispersion C. Interference D. Diffraction 17.He articulated that both the momentum and position of the electron can not be measured ex- actly at the same time. A. Max Plank B. Albert Einstein C. Werner Heisenberg D. Erwin Shrodinger 18. He first showed that light, being considered as a form of EM wave. A. Max Plank B. Arthur Compton C. Albert Einstein D. Clinton Davisson 19. It is made of water droplets of varying sizes. A. Rain B. Cloud C. Water droplets D. Thunder storm 20. Why is that rain clouds appear darker? A. Water droplets become bigger and denser and it can absorb more light than scatter it. B. Water droplets become bigger and denser and it can reflect more light than scatter it C. Water droplets become lower and less denser and it can absorb more light than scatter it. D. Water droplets become lower and less denser and it can reflect more light than scatter it 21. It occurs when 2 waves meet while travelling on the same medium. A. Scattering B. Dispersion C. Interference D. Diffraction 22. In what year, Max Plank was able to formulate and discover the so called Plank’s constant ? A. 1900 B. 1901 C. 1902 D. 1903 23. He proposed that light consists of tiny stream particles. A. Thomas Young B. Isaac Newton C. Louis de Brogile D. Christian Huygens 24. It is produced when light strikes a smooth surface. A. Rough Reflection B. Diffuse Reflection C. Regular Reflection D. Diffraction Reflection 25. It is responsible for this blue-colored sky and beautiful horizon. A. Scattering B. Interference C. Diffraction D. Refraction 26. It occurs when two waves meet while travelling on the same medium. A. Scattering B. Interference C. Diffraction D. Refraction 27. Made experiments showed that photons of X-rays decreased in energy when colliding with elec- trons. A. Arthur Compton B. Albert Einstein C. James Maxwell D. Christian Huygens 28. He proposed that wave has properties such as wavelength and frequency. A. Max Plank B. Lester Germer C. Louis de Broglie D. Arthur Compton 29. Why do we get easily sunburned in ultraviolet light but not in visible light? A. Because UV light has less energy than visible light B. Because UV light has more energy than visible light C. Because UV light has the same energy to visible light D. Because UV light has the longest wavelength than visible light. 30. Why is red light used in photographic darkrooms? A. Because red light enhances the quality of the photo. B. Because red light gives extra color to the photo C. Because red light does not ruin the pictures during the developing process. D. Because red light does not have any effect in developing process of photo, ESSAY TEST (10 points) 1. In a 1-2 paragraph essay, how would you imagine the world without light?