Physical Science

• • Diurnal Motion the apparent daily motion of the sky from east to west
• • Annual Motion It carries the sun eastward in the sky over the course of an entire year. Some of the heavenly bodies called the stars are fixed.
• • Wandering Stars/Planets A few of the heavenly bodies did not stay in the same place relative to the others.
• • Retrogade Motion The planets do not move relative to the fixed star but they change direction
• • Hipparchus Greek Astronomer noted that the position of the stars were shifted in a systematic way which indicated that they were not the one’s moving but the earth. This motion of the earth is called precession.
• • Precession proposed by Hipparchus
• Celestial Equator  a great circle onto the sky of the earth’s equator
• • Ecliptic Another great circle that intersects with celestial equator
• • Equinoxes Where ecliptic and the celestial equator intersect.
• • According to Aristotle rest is the natural state of the universe because most things we see are not moving.
• • Two types of motion Celestial and Horizontal/Violent
• • Celestial Motion Unchanging endless circular motion of heavenly objects in a sphere
• A.    Alternation Chemical change like burning and decay
• Natural/Vertical Puts objects in its natural position
• • Horizontal/Violent Happens when there is a force that moves an object
• • Eudoxus uses three concentric spheres and travels around a common center
• • Aristotle Model The spherical earth was at the center of the universe where the sun, moon, and planets revolve around it
• • Aristarchus Model The sun is at the center
• • Ptolemy all celestial objects including the planets, sun, moon, and stars orbited in epicycles
• • Nicolaus Copernicus Model The sun is at rest at the center of the universe
• • Tycho Brahe Model Earth is at rest at the center of the universe
• • Born 3 years after the death of Copernicus Tycho Brahe
• • Who recorded the positions of hundreds of stars Tycho Brahe
• • Galileo Galilei first to use a telescope to study the heavens
• • When did Galileo Galilei built his first telescope?

  1909
• The sun had dark patches that are called sunspot
• Who is Johannes Kepler?


  A German Mathematician who used Tycho Brahe's data
• The orbits of planets are ellipses with the sun at one focus. This shows that the planets do not move in uniform circular motion
• The line joining the planet to the sun sweeps out equal areas in equal intervals of time this shows that a planet sometimes moves quickly when it is closer to the sun and sometimes moves slowly when it is farther away
• The squares of the periods of the planet are proportional to the cubes of their average distance from the sun. This implies that the period for a planet to orbit the sun increases rapidly with the radius of its orbits
•  several problems can be solved with Kepler's third law such as the length of time it will take to reach mars in the most efficient orbit
• it will take 8.5 months to reach mars
• Kepler's third law can also determine how far from the center of the satellites do synchronous earth orbit
•  distance refers to the total path length traveled between two points
•  displacement refers to the change in position of our body relative to some reference point
• speed is the rate of motion
• an object moving at a constant speed in a single direction shows uniform motion
• velocity refers to the speed of an object in a particular direction
• Acceleration refers to the change in velocity of moving object per unit of time
•  speedometer is a device that measures instantaneous speed