physci
PhySci - 2nd Quarter
Part 1 - The universe
THE UNIVERSE
· The universe is everything.
· 13.7 billion years old.
· Theoretically born thru the big bang.
· It contains the stars, galaxies & all heavenly bodies.
THE EARTH
· Our home planet.
· Oblate Spheroid.
· Rotation: Sidereal & Solar
· Revolution: Sidereal & Tropical.
· Tilt: 23.5 Degrees
· Has one moon
· 3rd in the Solar System & the fifth largest.
THE EARTH'S FOUR SPHERES
1. Lithosphere
2. Atmosphere
3. Hydrosphere
4. Biosphere
· These are the four ingredients for life to exist.
GREEK'S VIEW ABOUT MOTION
Terrestrial Domain
· Aristotle believed that a force is needed to move; it does not move naturally.
· Interaction between nature.
· Expanded the idea:
o Alteration - Change in color of leaves; change in temperature.
o Generation - When organisms grow and die.
Natural Motion
· Without force, e.g., Newton’s Law of Motion, free fall.
Violent Motion
· With force.
· 4 elements: Fire, air, water & earth
CELESTIAL DOMAIN (DSAEP)
· Diurnal motion - Due to Earth’s rotation relative to stars.
· Stars move from east to west.
· Annual motion - Due to Earth’s revolution.
· Ecliptic - Path of the sun through the sky.
· Precession - Caused by gravitational forces from the moon and sun.
EARLY MODELS OF THE UNIVERSE (EAAPC)
1. Eudoxus of Cnidus:
o Homocentric Model.
o Stars, sun & moon revolve around the Earth.
2. Aristotle:
o Geocentric model
o A “sphere composed of spheres.”
3. Aristarchus of Samos:
o Heliocentric Model.
o The first to propose the sun-centered universe.
4. Ptolemy & Brahe:
o Geocentric Model;
o The Earth is immovable.
o Epicycle: Small circular orbit.
o Deferent: Large circular orbit, revolution.
5. Copernicus:
o Heliocentric; retrograde motion.
KEPLER'S LAWS OF PLANETARY MOTION (OAP)
1. Law of Orbits
o All planets move in elliptical orbits around the sun.
2. Law of Area
o Explains the rate of revolution of planets around the sun. The closer the planet, the faster it revolves.
3. Law of Periods
o Also known as the Law of Harmonies. It allows us to compare the orbital period with respect to the radius of the planet.
ARISTOTELIAN VS. GALILEAN VIEWS OF MOTION
1. Aristotelian View
o Natural & Violent motion
o A ball at rest will remain at rest—no concept of friction.
o The heavier, the quicker to fall.
2. Galilean View
o A ball at rest due to friction
o Free-fall experiments
o Mass does not affect the speed of objects in free fall.
o Did not know the concept of force.
ISAAC NEWTON'S LAWS OF MOTION (IAI)
1. Inertia
o A body at rest will remain at rest. A body in motion will continue its motion unless acted upon by an external force.
2. Acceleration
o The acceleration of an object is directly related to the net force and inversely related to its mass.
3. : Interaction
o For every action, there is an equal and opposite reaction.
MOMENTUM
· "Mass in motion"
· Velocity and mass.
· The greater the mass, the greater the momentum.
· The greater the speed, the greater the momentum.
· Velocity and mass are directly proportional.