Science 10 ZZ Class Notes - The Physical World: An Overview PDF

SCIENCE 10 ZZ - Class Notes i. The Retrograde motion of Mars - The apparent change THE PHYSICAL WORLD: in the direction of the motion AN OVE...

SCIENCE 10 ZZ - Class Notes i. The Retrograde motion of Mars - The apparent change THE PHYSICAL WORLD: in the direction of the motion AN OVERVIEW of Mars. Retrograde occurs when there is a difference in A. EUDOXUS OF CNIDUS speed of objects. ○ Model is based on observations ii. The existence of the phases ○ Sun, Moon and planets have uniform of Venus. circular orbits around the Earth ○ Modifications to the Geocentric ○ Orbits were fixed and celestial Model: bodies were not rotating. i. Deferent - Concentric circles ○ Created the 1st model of a around the Earth Geocentric Universe ii. Epicycles - Small circles Problems with Eudoxus’ model: with centers that move along ○ Brightness of planets change the deferent ○ Apparent size of moon changes iii. Equant - An imaginary point ○ Viewed from Earth, the motion of the where the Sun, Moon, and Moon as well as the Sun and the planets rotate. Planets is not Uniform iv. Inferior Planets - Mercury B. ARISTARCHUS OF SAMOS and Venus ○ Earth and Planets take on circular v. Superior Planets - Mars, orbits around a fixed sun Jupiter, and Saturn ○ The moon orbits around the Earth ○ Orbits are still perfectly circular but ○ Model is dubbed as the Heliocentric not concentric Model D. NICOLAUS COPERNICUS ○ Stellar Parallax - apparent shift of ○ Planets have uniform circular orbits the object with the respect of the around the Sun background. ○ Sun does not move ○ Celestial Sphere- Perfect shape ○ Earth moves faster than other followed by all heavenly bodies Planets, thus the Retrograde motion. C. CLAUDIUS PTOLEMY ○ Stellar parallax is not observable ○ Improved on the Geocentric model. because stars are far away. The geocentric model could not E. TYCHO BRAHE explain:  ○ Made precise observations even ○ Observed craters on the moon- the before the invention of the moon is not perfectly spherical telescope. ○ Observed sunspots- the sun is ○ Observations were used by later imperfect and rotating astronomers. ○ Observed the moons of Jupiter- ○ Found no parallax for the stars. moons are not unique to Earth only (Stars were too far away that ○ Observed the Phases of Venus- parallax was too small to measure) Venus orbits the Sun relative to the ○ He was able to catalog thousand Earth stars accurately. ○ Observed that stars are pinpoint ○ Assumed the existence of even when viewed through a supernova telescope F. JOHANNES KEPLER CONCERNS WITH HELIOCENTRISM ○ Concluded that no combination of a. We do not feel the motion of the circular deferents and epicycles Earth could account for the available data b. No stellar parallax ○ Developed simple laws that c. Not philosophically attractive accounted for observations. H. ISAAC NEWTON ○ Introduced terms perihelion (the ○ Newton’s Contributions: point in planet’s orbit when it is i. Calculus closest to the sun) and aphelion (the ii. Optics point in planet’s orbit when it is iii. Laws of Motion farthest from the sun) iv. Gravitation ○ Kepler’s 3 Laws of Planetary ○ Newton’s Laws of Motion: Motion i. First Law: Law of Inertia - A i. The orbits are ellipses body at rest will remain at ii. Planets cover equal areas in rest, and a body in motion equal time unless it is acted upon by an iii. A planet’s orbital period is external unbalanced force. proportional to the size of its ΣF=0 orbit (the farther the planet, the ii. Second Law: Law of longer the time to orbit) Acceleration - The G. GALILEO GALILEI acceleration of the object is directly proportional to the  force and inversely NEWTON’S LAW OF UNIVERSAL proportional to the mass GRAVITATION iii. Third Law: Law of Action 𝑚1 𝑚2 ○ 𝐹 = 𝐺 2 𝑟 and Reaction - The force ○ The higher mass, the more exerted by object 1 upon attraction object 2 is equal in ○ r = distance between the two magnitude and opposite in objects direction to the force exerted ○ if r decreases, attraction will by object 2 upon object 1. increase ○ Newton’s Laws of Universal Gravity: ○ Henry Cavendish- proved the value of G = 6.67 x 10-11 N VECTORS AND SCALARS m²/kg² Scalar - magnitude without direction ○ Newtonian Physics- cannot Vector - magnitude with direction explain the erratic movement and unit of mercury around the Sun ○ Examples: displacement, velocity, acceleration, force” ELEVATOR DILEMMA LAW OF INERTIA APPLICATIONS: Case 1: elevator is not in motion ○ Stirring liquid (viscosity) ○ Weight is normal ○ Vehicle ride (wearing a Case 2: going up (accelerating seatbelt) upwards) ○ Ketchup example ○ Weight is greater LAW OF ACCELERATION Case 3: going down (accelerating FORMULA: downwards) ○ 𝐹𝑜𝑟𝑐𝑒 = 𝑚𝑎𝑠𝑠 × 𝑎𝑐𝑐𝑒𝑙𝑒𝑟𝑎𝑡𝑖𝑜𝑛 𝑓𝑜𝑟𝑐𝑒 ○ Weight is lesser ○ 𝑎𝑐𝑐𝑒𝑙𝑒𝑟𝑎𝑡𝑖𝑜𝑛 = 𝑚𝑎𝑠𝑠 Case 4: free-fall → Net force is the amount of force left over once you've added together ○ Weightlessness (zero weight) all of the forces that might cancel each other out. EINSTEIN’S THEORY OF RELATIVITY LAW OF ACTION AND REACTION ○ Albert Einstein- Challenged APPLICATIONS: Newton’s picture of universal ○ Walking gravitation ○ Swimming - push the fluid ○ “Mass and energy are both but backward to swim forward different manifestations of the same  thing — a somewhat unfamiliar —--------------- conception for the average mind.” ○ SPECIAL RELATIVITY - all about comparing physical effects from different observer positions in terms of velocity or speed in a particular direction. ○ GENERAL RELATIVITY - explains the physics of all situations. ○ Gravity itself wasn't a force but rather an effect; a distortion in the shape of space due to mass. →The planets didn't follow certain paths because of the attraction of the sun’s gravity, but because the space before them was covered by the sun's mass. Any observer can detect the position or velocity of any quantum principle, at any given time interval, but not both at the same time. HYPOTHESIS vs. LAW vs. THEORY Common Misconception: ○ Hypothesis → Theories → Laws Hypothesis - an educated guess, minimal explanation of a phenomena Facts - observations shown to be true, can be easily proven via evidence ○ Theory - explains why it happens ○ Law - explains what happens