Physical Science Reviewer (2nd Quarter) PDF

PHYSICAL SCIENCE REVIEWER (2ND QUARTER) *Note: please do have a thorough review on the included concepts, terms, & individuals in this reviewer. All of the handouts are available in our google drive folder. Thanks, and may the force be with you. UNIVERSE AND PHYSICS MODELS OF THE UNIVERSE...

PHYSICAL SCIENCE REVIEWER (2ND QUARTER) *Note: please do have a thorough review on the included concepts, terms, & individuals in this reviewer. All of the handouts are available in our google drive folder. Thanks, and may the force be with you. UNIVERSE AND PHYSICS MODELS OF THE UNIVERSE o UNIVERSAL MODELS ▪ The early humans relied on the skies as their principal means of telling the time, of navigation, and of knowing when to start planting crops ▪ 3,000 years ago, Egyptians established a 365-day calendar based on the movements of the celestial body Sirius. This Track also coincided with the annual flooding of the Nile. Babylonians and Assyrians also created similar calendars to aid them in farming. ▪ Around 2,560 BCE (Before Common Era), Egyptians built the Pyramids in Giza, constructed in such a way that each side of the pyramid faced the four (4) cardinal directions (i.e. North, South, East, West), with a 0.1° aberration, with the three (3) pyramids aligning at the constellation Orion's "belt". ▪ Constructed in 3,000 BCE, the Stonehenge in Wiltshire, England was thought to have been an observatory used to predict eclipses. It was constructed in a way that the Sun aligns with the "Friar's Heel" stone during the summer solstice (around June 20-22 annually). ▪ Another pyramidal structure, the Chichen Itza found in Yucatan, Mexico, have windows at the top and sides that allowed sunlight to illuminate the rooms they contain within. It was said that during equinoxes (both vernal [March 20-22] and autumnal [September 20-22] annually), the pyramid's stairs create an illusion of serpents crawling downwards due to the way they are illuminated during sunset. STONEHENGE CHICHEN ITZA o GEOCENTRIC - the Earth and the other heavenly bodies were assumed to be spheres. ▪ Pythagoras, Ptolemy, Plato, Anaxagoras, Aristotle, Anaximander, & Eudoxus. ▪ Aristotle’s motion:  - Aristotle geocentric model o HELIOCENTRIC - Before the heliocentric model carne about, Greek astronomer Philolaus initially proposed a PYROCENTRIC model of the Universe. According to him, neither Earth nor the Sun was the center of the Universe. Planets and heavenly bodies were supposed to move around a ‘FIRE” located at the center of the Universe. In 300 BCE, another Greek astronomer Aristarchus proposed the first heliocentric model of the Universe by considering Philolaus’ “central fire” as the center of the cosmos. In this model, the sun and the other known planets revolve around this “central fire”. Aristarchus also placed the other known planets at that time based on their distances from the sun. However, his theory did not last because of the general acceptance of the Ptolemaic model. ▪ Philolaus, Aristarchus, Nicolaus Copernicus, Galileo Galilei, Tycho Brahe ▪ Tychonic model – Tycho was not a Copernican, but proposed a "geo-heliocentric" system in which the Sun and Moon orbited the Earth, while the other planets orbited the Sun. ▪ Galileo Galilei - Craters and mountains on the Moon - The Moon’s surface was not smooth and perfect as received wisdom had claimed but rough, with mountains and craters whose shadows changed with the position of the Sun. - The phases of Venus; The planet Venus showed changing crescent phases like those of the Moon, but their geometry could only be explained if Venus was moving around the Sun rather than the Earth. - The planet Jupiter was accompanied by four tiny satellites which moved around it. These are now known as the Galilean moons: Io, Ganymede, Europa and Callisto. - Galileo saw that the Milky Way was not just a band of misty light, it was made up of thousands of individual stars. o THE SOLAR SYSTEM TODAY ▪ consisting of eight planets, with the sun as its center, and the planets revolve around the sun while spinning about their axes. ▪ made up of zones - innermost zones are occupied by the terrestrial planets Mercury, Venus, Earth, and Mars (rocky, metallic, and comparatively small) - asteroid belt, where leftover rocks from the Solar System formation can be found. - beyond the asteroid belt is the gas giants' realm -- Jupiter, Saturn, Uranus, and Neptune - beyond the orbit of Neptune lies the Kuiper Belt, which consists of small celestial bodies - Pluto, which used to be a planet, is now classified as a “dwarf planet.” In 2006, Pluto lost its status as a planet because it is incapable of clearing debris off its orbital neighborhood.  - four other dwarf planets in our solar system are known today -- Ceres, Haumea, Makemake, and Eris -- although more are being discovered each day. - Biyo is an asteroid in the inner asteroid belt of our solar system CELESTIAL MECHANICS o CELESTIAL SPHERE ▪ Ancient Greeks considered Earth to be enclosed in a hollow sphere, where the stars, the sun, and other heavenly bodies are embedded ▪ the heavens' motion was caused by the rotation of the celestial sphere about a fixed Earth. ▪ points where the Earth’s rotational axis cuts this sphere are called the north celestial pole (NCP) ▪ south celestial pole (SCP) ▪ celestial equator is the projection of the Earth’s equator in the celestial sphere. ▪ path that the sun appears to take around the celestial sphere is called the ecliptic. ▪ inclined 23.5° concerning the celestial equator ▪ two points on the ecliptic with the celestial equator's greatest distance are referred to as solstices: - The sun is at its northernmost position above the celestial equator or, at its highest in the sky, is called the summer solstice. - June solstice because it happens on or near June 21 - day is longest, and night is shortest - winter or December solstice occurs when the sun is at its southernmost position or its lowest in the sky - happens on or near December 21 - day is shortest while the night is longest during the winter solstice ▪ two points where the ecliptic intersects the celestial equator are known as equinoxes - equinoxes, Earth’s rotational axis is perpendicular to the line joining Earth and the sun - day and night are of equal duration - autumnal equinox happens on or near September 22 - vernal or spring equinox happens on or near March 21 ▪ Earth's aphelion occurs in early July, and its perihelion occurs in early January ▪ Aphelion - Earth is farthest from the sun in early July, about 14 days after the June solstice. ▪ Perihelion - Earth is closest to the sun in early January, about 14 days after the December solstice ▪ ecliptic traces through a series of star fields are called constellations, as defined by the International Astronomical Union ▪ sequence of constellations is called the zodiac ▪ located where the sun crosses in the sky. ▪ Different sets of constellations are visible in Earth’s night sky at different times of the year o DIURNAL MOTION AND ANNUAL MOTION o It takes 24 hours for the Earth to rotate about its axis from west to east (from east to west) o DIURNAL MOTION  ▪ daily motion of stars and other celestial bodies across the sky caused by the Earth’s rotation about its axis ▪ is responsible for the daily rising and setting of the sun and the stars. o ANNUAL MOTION ▪ Earth also revolves around the sun once a year ▪ the sun also apparently changes position in the celestial sphere, moving each day about one degree to the east relative to the stars. ▪ Earth’s revolution around the sun ▪ accounts for the visibility of a zodiac constellation at a specific time of the year ▪ it is also responsible for the seasons LAWS OF PHYSICS o BASICS OF MOTION o MOTION - is defined as the change in position over a given time - everything behaves linearly, so the objects and scenarios involved are only moving along one (1) of the three (3) known axes that we use (x, y, z). - e.g., a car driving along the straight highway, without any other cars interfering with its movement. o DISTANCE is the total measured length between two (2) given points. e.g., simple racetrack, it is measured from Start to the Finish line. o DISPLACEMENT is the measured mean distance covered between two (2) specified points; is a certain distance at any given two (2) points. e.g., the displacement could be from Start to the middle, middle to the Finish line, or it could also be the average distance between the Start and the Finish line, used interchangeably with distance. o TIME is the progression of events occurring between instances. We need to prove that there is a progression between events. e.g., from walking to running, jogging from point A to B, and so on. o SPEED, VELOCITY, AND ACCELERATION o SPEED is the scalar quantity defined as the total distance covered per unit time; if there is motion, there is speed. Speed does not and cannot have a negative value. Sometimes, it is interchanged with velocity. o VELOCITY is the measured speed measured between two (2) specified point; measured speed at a certain distance at any given instance in time; a vector quantity and requires direction Note: Negative velocity values indicate that the objects are moving in the opposite direction. o ACCELERATION is the change in velocity per unit of time; shows how fast the object moves to reach that certain amount of velocity within a certain amount of time. Note: Negative acceleration values indicate that the objects are slowing down. o FREE-FALL - a motion wherein only gravity is the only acting influence on the object. gravity pulls everything towards its center, it is safe to say that gravity is the only driving mechanism in an object’s vertical motion. Acceleration here is nearly constant since gravity is the only influence here. Known as lowercase 𝑔, the value of acceleration due to gravity is calculated to be 9.8 m/s2, or 32.2 ft/s2. Air resistance is “irrelevant” in classic free-fall, providing an “ideal” setup for its cases. e.g., being thrown upwards or dropped downwards in its classical take; Suppose a man went skydiving, jumping off his King Air 12,000 feet above the ground, going from zero to 175 m/s within a short amount of time. This is an example of free-fall, another case of rectilinear motion.  o PROJECTILE MOTION - is a free-falling motion where an object, usually referred to as a projectile, flies over the air at a certain angle; object’s path is known as its trajectory. As it flies in the air, the velocity it gains has both horizontal and vertical components. This, along with the angle the ballistic is being thrown at, creates a parabolic trajectory. NEWTON’S LAW OF MOTION o LAW OF INERTIA - Newton’s First Law, the Law of Inertia, states that an object will remain in its current state unless there is a change in its equilibrium caused by an unbalanced, outside force. - In the given definition, equilibrium is stated. Equilibrium is balance. The state of an object’s equilibrium is known as its inertia (Latin, inactive). Inertia is best defined as the resistance of an object to change its state of motion. If acceleration is absent (i.e., 𝑎=0 𝑚/𝑠2), the object is in a state of rest. o LAW OF ACCELERATION - An object is said to be accelerating if an unbalanced net force is applied to it, in which the acceleration of the object is directly proportional to the net force, is moving along the direction the net force is directed at and is inversely proportional to the object’s mass - represents the aftermath of an object exposed to unbalanced forces, states that an object is said to be moving when it is accelerating. According to this law, acceleration is directly proportional to the prevailing unbalanced force (called net force) and inverse to its mass. FORCES ▪ Weight (𝑭𝑾) is the force exerted by gravity on the object, represented by the formula, 𝐹𝑊=𝑚𝑔, with 𝑔 is the acceleration due to gravity (going down). ▪ Normal Force (𝑭𝑵) is the force acting against weight, which is always perpendicular to the surface the object is resting upon (going up). ▪ Frictional Force, or friction (𝑭𝒇) is the resistance of a surface or an object acting upon another object in contact with it (going left). ▪ Applied Force (𝑭𝒂𝒑𝒑) is the force directly applied to an object (going right). o LAW OF INTERACTION - For every force, there is always an equal – and opposite – reaction to it. - This law’s premise is simple: there is always an equal – and opposing – the amount of force counteracting against another force - Third Law explains the First and Second Laws. - Normal force (𝐹𝑁). In it, the normal force is always paired with weight (𝐹𝑊), which is the normal force’s polar opposite. - The two forces, when paired together, are called interaction force-pairs. Other force pairs are applied force and friction, weight and air resistance, applied force and tension, and so much more - explains how things get to move. - E.g., fish uses its tail to push away the water. But, as explained by the other Laws, water propulsion allows the fish to move forward. Another example is the interaction between friction, applied force, weight, and normal force when walking.  o GRAVITY - Overview Gravity (Lat. gravis, “heavy”) is a force that pulls everything towards its center. Everything on Earth is experiencing its influence -- from the glass of water spilling to the floor to the aching feet of standing commuters, up to the divers diving off from a cliff into the ocean (hence the phrase, “What comes up, must go down."). LAW OF CONSERVATION o CONSERVATION LAWS o LAW OF CONSERVATION OF MASS AND LAW OF CONSERVATION OF ENERGY - The Law of Conservation of Mass dates from Antoine Lavoisier's 1789 discovery that in chemical reactions, the reactants' total mass equals the total mass of the products. The total mass of an isolated system is constant. As referred to here, an isolated system is a system where no mass enters or leaves during an interaction. - With the famous equation, 𝐸=𝑚𝑐2, Albert Einstein showed that mass and energy are equivalent. This shows that mass can be converted into energy and vice versa. - two laws have been accounted for: the law of conservation of mass and the law of conservation of energy (which, when together, is called the law of conservation of mass and energy). - Both laws suggest that energy and mass cannot be merely created nor lost in a reaction. - Both undergo a change that is still accountable in the total system. - Mass, for instance, is converted into smaller chunks of mass and the lost ones as energy. - energy is converted into new forms of energy, or if the mass-energy equivalence is used, converted back into the mass. o COLLISION - the brief, simultaneous interaction between two or more bodies due to the internal force acting between the bodies. It involves energy, force, velocity, momentum, and impulse. This is the direct application of momentum and impulse that involves forces, mass, and velocity. It applies another Conservation Law: The Law of Conservation of Momentum, wherein momentum is a constant in all things that have mass. - vector sum of all given momenta (sing. momentum) of all objects within a system, that sum cannot be changed by any other interactions within that system. Simply put, if one object has momentum within a certain direction, the other objects must have the same momentum, but traveling in directions opposite that of the other. - E.g., does not only imply the hard-hitting impact between two cars, even the simplest ones, such as playing Billiards (a classic example), playing volleyball, & walking - There are two kinds of collisions, both of which conserve momentum. They will only differ whether energy (implying kinetic energy) will be conserved or not. ELASTIC COLLISION is defined as a type of collision where the concerned bodies conserve both energy and momentum upon contact with each other. o E.g., describe this type of collision is a ball bouncing off the floor. Sure, the ball will bounce upon hitting the ground, and it will conserve momentum and energy. CONTACT COLLISION is not a perfect collision. The other type, which is a non-contact collision, is almost perfect. The non-contact collision is a kind of elastic collision where the objects interact with each other, even without direct contact. o E.g., each bounce will conserve less and less energy due to the force being weaker with each succeeding bounce until it will stop altogether; a planet slinging a space shuttle in another direction. head-on collision is the type of elastic collision where the projectile moves directly along a straight line. Upon colliding with the projectile, the target will then move in the direction the projectile is moving at. non-head-on collision is the type of collision where the projectile hits the target at a certain angle. The resulting angle after impact depends on the masses of the given objects in a collision. INELASTIC COLLISION occurs more often than elastic collision because, in reality, energy is lost more than being conserved.  o E.g., evident in vehicular accidents, target ranges, or even in simple pastimes like playing football in all its variants (American, soccer, and rugby), and, as young kids, throwing clay at the wall. FUNDAMENTALS OF A WAVE, ELECTRICITY, AND MAGNETISM o Wave – disturbances propagated in a medium (or in vacuum) that carry energy ▪ Mechanical waves require a medium to propagate Examples: sound, earthquakes, ripples, vibrations on a guitar string ▪ Electromagnetic waves can propagate in a vacuum (RMIVUXG) Classifications: i. Longitudinal waves are waves where the particles in the wave vibrate and move along the wave ii. Transverse waves are waves where the particles in the wave vibrate and move against the wave. This is perpendicular ▪ Frequency – the number of waves produced in each period - unit is Hertz (Hz) ▪ Wavelength – the distance between any two (2) successive points in a wave that are in phase with each other ▪ Wave speed – the distance where a wave travels per unit time ▪ Charge – fundamental physical quantity responsible for electrical phenomena - unit is Coulomb (C i. Positive charge (proton) = 𝟏.𝟔 × 𝟏𝟎−𝟏𝟗𝐂 ii. Negative Charge (electron) = −𝟏.𝟔 × 𝟏𝟎−𝟏𝟗𝐂 o Ways of charging: a. Rubbing b. Conduction c. Induction ▪ Net Charge – sum of all positive and negative charges in the object ▪ Law of Conservation of Charge – if a system starts with equal charge distributions, the system will be in a state of equilibrium, unless a charge is added or removed from the system (Benjamin Franklin) ▪ Coulomb’s Law – Electric force is determined by the product of two (2) charge values multiplied to a proportionality constant, and divided by the square of the distance between the charges ▪ Electric Field – field existing in a region around a charged particle ▪ Magnet – material capable of interacting with other materials easily influenced by magnetism - name came from the place Magnesia in ancient Greece, where most lodestones in the ancient world were found  ▪ Magnetic pole – region of a magnet that is polarized ▪ Magnetic field – field of force surrounding a magnet - created from changing electric field, which is generated from moving charges - dictated by the right-hand rule ▪ Magnetic Flux – measure of a magnetic field strength per area; unit is Weber (𝟏 𝐖𝐛 = 𝟏 𝐕 ∙𝐬) - in a closed surface, total magnetic flux is equal to zero (0) ▪ Law of Magnetic Poles – like Coulomb's Law, wherein charges are replaced with polarity (i.e., like poles repel, unlike poles attract) ▪ Electric Flux – strength of an electric field over an area in a field region ▪ Electric Current - Amount of charge in conductor per unit time; unit is Ampere (A) = 𝟏 𝐂/𝐬 Types: a. Direct – current has both constant voltage and direction, primarily used in battery- operated devices b. Alternating – current direction and magnitude changes in between two extreme values, periodically reverses direction, and used in daily living Kinds: a. Conventional – current flows from positive terminal of the source towards the negative b. Electron – current flowing in opposite from the conventional, flowing from the negative terminal of the source towards the positive ELECTROMAGNETISM o branch of physics that studies the relationship between electricity and magnetism. o an electric current produces a magnetic field, and a changing magnetic field produces an electric current. o MAGNETISM FROM ELECTRICITY - While doing a demonstration in physics in 1820, Danish physicist Hans Christian Oersted discovered that a moving charge or a current-carrying wire produces a magnetic field around it in addition to its electric field. The direction of the magnetic field in a straight wire can be determined by following the "right-hand rule". - Shortly after Oersted announced his discovery that a current-carrying wire produces a magnetic field, French physicist André-Marie Ampere conducted experiments and concluded that electric current passing through a coil or a solenoid produces a magnetic field. - A solenoid is simply a long coil of several turns of wire.. GEOMETRIC OPTICS o REFLECTION – change of a wave’s direction between two (2) media in such a way the wave returns to the medium it originally came from a. Incident Ray – the light at its point of entry b. Incident Angle (𝜽𝒊) – the light's angle upon entry c. Reflected Ray – the light at its exit point after reflection d. Reflected Angle (𝜽𝒓) – the light's angle upon reflection e. Normal – the imaginary line that bisects the incident and reflected angles, which serves as the point of incidence during reflection Reflection Types: Specular – reflection occurring at smooth surfaces, where light rays are reflected without breaking up, resulting in a reflection with one incidence Diffuse – reflection occurring at rough surfaces, where light rays break up at uneven surfaces, reflecting at different angles o REFRACTION – change of a wave’s direction between two (2) media in such a way that the wave slows down upon entry to the second medium and changes direction a. Refractive Index (𝒏) – dimensionless quantity that describes how fast light travels through a material (called a medium) 𝒏 =𝒄 𝒗 Where, 𝒄 = speed of light in a vacuum =𝟑×𝟏𝟎𝟖 𝐦/𝐬 𝒗 = speed of light in a given medium b. Refraction Angle (𝜽) – angle at which the light ray is refracted and exits the medium c. Snell's Law – mathematical description of refraction 𝒏𝟏𝐬𝐢𝐧𝜽𝟏 = 𝒏𝟐𝐬𝐢𝐧𝜽𝟐 d. Total Internal Reflection – phenomenon that dictates the behavior of how light is refracted in a medium, resulting in three (3) different cases i. Critical Angle (𝜽𝒄) – angle where light bends at the boundary between the first and second media o MIRROR – an optical device where light is reflected and reconvened to form images a. Plane Mirror – a mirror with a flat surface and can only form virtual images; has right-left reversal for its virtual image b. Convex Mirror – a curved mirror whose surface bulges outward, where the image formed is similar to a concave lens c. Concave Mirror – a curved mirror whose surface bulges inward, where the image formed is similar to a convex lens o LENS – from the Greek word for lentils, also known as a “thin lens”, is an optical device where light is refracted to form images, without undergoing dispersion and aberration, wherein it depends on how its surface is curved a. Convex Lens – a lens wherein its surface bulges outward, forming large virtual images to the left of the objects; also known as a converging lens b. Concave Lens – a lens wherein its surface bulges inward, forming small virtual images at the right side of the objects; also known as diverging lens  COLORS OF LIGHT