PHYSICAL SCIENCE

• 1. Nicolaus Copernicus - He was a student of Plato. For him, the earth is spherical in shape since it always casts a curved shadow when it eclipses the moon.
• 2. Tycho Brahe - Using his mentor's data, he formulated the three laws of planetary motion: the law of Ellipse, Law of Equal Areas, and the Law of harmonies.
• 3. Johannes Kepler - He believed that only the sun and the moon revolved around the earth;
• 4. Galileo Galilei - He was the greatest Italian scientist of the Renaissance. Due to the telescope,
• 5. Isaac Newton - He developed and formalized Galileo's concept of inertia. He conceptualized the force of gravity and he was able to provide an explanation for the elliptical orbits.
• 1. Astronomical unit (AU) - the unit of length defined as the average distance between Earth and the Sun; this distance is about 1.5 × 108 kilometers or 1.5 x 1011 metres
• 2. Eccentricity - in an ellipse, the ratio of the distance between the foci to the major axis
• 3. Ellipse - a closed curve for which the sum of the distances from any point on the ellipse to two points inside (called the foci) is always the same
• 4. Focus - (Plural:focil) one of the two fixed points inside an ellipse.
• 5. Kepler's first law - each planet moves around the Sun in an orbit that is an ellipse, with the Sun at one focus of the ellipse
• 6. Kepler's second law - the straight line joining a planet and the Sun sweeps out equal areas in space in equal intervals of time
• 7. Kepler's third law - the square of a planet's orbital period is directly proportional to the cube of the semimajor axis of its orbit
• major axis - the maximum diameter of an ellipse
• 8. Orbit - the path of an object that is in revolution about another object or point
• 9. orbital period (P) - the time it takes an object to travel once around the Sun
• 10. Orbital speed - the speed at which an object (usually a planet) orbits around the mass of another object.
• 11. semi major axis - half of the major axis of a conic section, such as an ellipse
• 1. 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.
• 2 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.
• 1. 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.
• 1. 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.
• 1. First Law The Law of Ellipses -

  When Kepler tried to figure out Mars' orbit, it did not fit the then-famous theory that a planet follows a circular path.
• 2. Second Law The Law of Equal Areas -

  The second law, states that when an imaginary line is drawn from the center of the Sun to the center of a planet,
• 3. Third Law The Law of Harmonies -

  describes that the square of a planet's orbital period (T2) is proportional to the cube of a planet's average distance from the Sun (R3).
• Galileo Galilei 1564-1642

  • Galileo developed the first concept of laws of motion.
• Galileo - • Developed the concept of motion in terms of velocity (speed and direction) by using inclined planes.

  : Developied theated fare that caufen motor is rest or uniformed motion.

  • Developed the idea that objects resist motion, inertia.
• According to Galileo, objects in motion eventually stop because of a force called friction.
• Friction - is a force that opposes motion between any surfaces that are touching.
• Isaaw Newton‘s First Law of Motion -

  Mass and Inertia -

  An object's inertia depends on its mass.
• Mass - is the amount of matter or substance that makes up an object.
• Isaac Newton - was born the same year Galileo died. ___ law of inertia is based on Galileo's idea of inertia. He expanded Galileo's work and came up with his Three Laws of Motion.
• Newton's first law of motion states that...

  An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.
• Inertia of rest - an object will stay in place unless something or somebody moves it.
• • Inertia of motion- an object will continue at the same speed until a force acts on it.
• • Inertia of Direction- an object will stay moving in the same direction unless a force acts on it.
• Forces - what causes an object to move.
• • Force - is defined as a push or a pull.
• • One Newton is the amount of force required to give a 1-kg mass an acceleration of 1 m/s/s. Thus, the following unit equivalency can be stated as:

  1 Newton = 1 kg • m/s
• Friction - A rolling marble on the floor that suddenly stops when it reached a rough surface does not stop because of the absence of a force, it stops because of the presence of a force called friction. (Mang slow down for aj example eraser rubbing something)
• Friction - is a force that opposes motion between any surfaces that are touching.

  • Friction - occurs because no surface is perfectly smooth.