– the movement of celestial bodies, galaxies, and other cosmic objects.

a simplified representation of a real-world system or phenomenon.

entity that consists of interrelated parts or components.

The Ancient Greeks considered Earth to be enclosed in a hollow sphere called the___. Where the stars, the sun, and other heavenly bodies are embedded.

the points where autumnal Earth's rotational axis cuts this sphere

the projection of Earth's equator in the celestial sphere.

the path that the Sun appears to take around the celestial sphere. It is inclined 23.5° with respect to the celestial equator

thetwo points or two days in a year in which the Sun (ecliptic)is at the farthest declination (north orsouth) from the celestial equator

the two points or two days in a year where the Sun (ecliptic)crossesthe celestial equator. At the equinoxes, Earth's rotational axis is perpendicular to the line joining Earth and the sun. On those days, day and night are of equal duration.

point where the sun is at its northernmost position above the celestial equator or at its highest in the sky. -happens on or near June 21 and day is longest and night is shortest

occurs when the sun is at its southernmost position or at its lowest in the sky-happens on or near December 21-day is shortest while night is longest

happens on or near September 22

happens on or near March 21

Earth is not a perfect sphere. It bulges a bit in the equator because of the pull of the moon and the sun. As a result, Earth's axis changes direction over a period of time. Such change in the orientation of the rotational axis of any rotating body is termed______

the apparent daily motion of stars and other celestial bodies across the sky caused by Earth's rotation about its axis. -responsible for the daily rising and setting of the Sun and the stars

the apparent yearly motion of Sun caused by Earth's revolution around it. accounts for the visibility of a zodiac constellation, it is also responsible for the seasons like winter

occur when either the Earth or moon cast a shadow into each other. The ancient Greeks deduced that the Earth is spherical. During a ____, the shadow cast by the Earth is circular. The direction in which the shadow is cast points to a sphere

3 000 years ago; established a 365-day calendar based on the track of the star Sirius (brightest star in the night sky). This track also helped determine the annual flooding of the Nile River

(2560 BC) –constructed in such a way that each side faced north, south, east, or west of a compass to within a tenth of a degree. it represent the belt stars of the constellation Orion

was thought to have been an observatory used to predict solar and lunar eclipses. It was constructed so that in the summer solstice, the sun would rise above one of the main stones

occurs when the moon passes between the Earth and sun with the moon casting a shadow on the Earth’s surface. may occur only during the new moon phase

occurs when the Earth is directly aligned between the sun and moon with the Earth casting a shadow on the moon. may occur only during the full moon phase

theorized the structure of the universe in which the Earth is assumed to be at the center of it all

planets and heavenly bodies were supposed to move around a "fire" located at the center of the universe

is the most widely accepted model in the present day. asserted that Earth spins on its axis every day and revolves around the sun like the other planets; only the moon orbits the Earth.

this model was a hybrid of the geocentric and heliocentric models. It placed the Earth at the center of the universe, while the Moon and Sun revolved around it. All other planets revolve around the sun.

Proponent of Geocentric Model

Proponent of Pyrocentric Model

Proponent of Heliocentric model

- Maintained the concept of epicycle.

- Proposed that planets nearer to the sun revolves faster than those that are far.

Proponent of Tychonic Model (late 16th century). A Danish astronomer who conducted precise observations of the positions of the planet during his time.

All planet revolves around the Sun but in a flattened circular orbit. The sun is located at one of the foci of an ______.

The ______of planetary motion states that orbits of the planet are ellipses, with the sun at a focus.

The _____ of planetary motion. This compares the orbital period and radius of the orbit of one planet to other planets. The farther a planet is from the sun, the longer its period of revolution

The _____ of planetary motion. This states that a planet sweeps out equal areas in equal times during its orbit. A planet moves faster when it is closer to the Sun because of the strong gravitational pull and slower if it is farther.

Heliocentric Model Solidified: _____ provided strong support and evidence in favor of the heliocentric model. It became widely accepted that the Sun was at the center of the solar system.

An object moves and returns to its natural state depending on the composition that object is made of.

The heavier the object was, the faster it would fall.

thought to occur when objects moved toward their natural place in the universe

– happens when object moves after an external force, such as pushing or pulling, is applied to it. - No motion will take place unless there is a “mover” in contact with an object.

requires an external continuous force to keep an object in motion.

•Any object not in its natural place will strive to get there. He called it Natural Motion.

•Object fall at a rate proportional to their weight. Heavier objects falls much faster than lighter objects

Force is needed to start and sustain the motion of an object.

motion caused by external forces acting on an object, such as pushing or pulling.

carries a force that propelled it forward. As this force gradually diminished, it would eventually fall to the ground.

All objects, regardless of mass, fall at the same rate in the absence of air resistance.

• Force is not needed to sustain motion of an object.

• BUT! Force is required to change motion.

A projectile is influenced by vertical motion due to the force of gravity and horizontal motion that is uniform

the change of position of an object with respect to time.

adding all distances travelled. • Does not depend on direction. Always positive or zero. never negative

adding all distances but considering its direction. can be positive, negative or zero depending on the direction

A physical quantity that has only a magnitude (size)

A physical quantity that has both a magnitude (size) and a direction

how fast an object is

speed with direction

n is a vector quantity that describes how an object's velocity changes over time. It also includes both magnitude and direction

Interaction between two objects that causes a change in the motion of the objects

An object free to move will move once acted upon by force.

any force that occurs as a result of two objects making contact with each other

a force which acts on an object without coming physically in contact with it

“An object at rest will remain at rest, and an object in motion will remain in motion unless it is acted by an external force and unbalanced forced.”

“The ______of an object is directly related to the NET FORCE and inversely related to its mass.”

“To every action, there is always an equal but opposite reaction.”

• equal (in magnitude)

• opposite (in direction)

It is the property of a body that tends to resist a change in its state of motion. The measure of ___is MASS.

It is the amount of matter/ atoms in a body

It is the gravitational force acting on a body.

As we move through the universe, mass stays constant, while weight changes. An object's weight is less on the moon due to a weaker gravitational force

It is the rate of change of velocity of an object with respect to time. An object is said to be accelerating or have acceleration when its velocity is changing.

The acceleration of an object is directly proportional to the ____

– increase in ______increases acceleration

The acceleration is INVERSELY PROPORTIONAL with its ____

– increase in _______ decreases acceleration

– bouncing of light when it reaches a surface or a boundary between two media

– bending of light due to its change in its speed when it obliquely passes two different media

is a measure of how much a material can bend light. A higher ___means that light will slow down more and bend more when entering the material.

separation of white light to colors (rainbow) due to refraction

refers to passing of light through a material without being absorbed

an object appears with a particular color means that it only reflects one color while absorbing the rest

a. Black absorbs all light

b. White reflects all light

Occurs when light strikes a SMOOTH surface

Light rays are reflected in ONE direction

- Occurs when light strikes a ROUGH surface

- Light rays are reflected in RANDOM directions.

- Light can be transmitted without change of direction

- Light can be pass but scattered in many directions

- No light passes; therefore, all light is either reflected or absorbed

When light passes from one medium to another, then a part of the light is absorbed by particles of the medium

occurs when particles absorb light and scatter it in all directions.

Particles in the atmosphere scatter violet the most, followed by blue, green, and so on.

depends on the relative size of the particles and the wavelength of light

– by particles smaller than light

– blue color of the sky

refers to the scattering of mostly white light and depends less on the wavelength.

– by particles same size of light

– white color of clouds and fog

It is the spreading of light when it encounters an obstacle or an opening.

depends on the size of the opening and the wavelength of light

It is the combination of two or more waves into one wave whenever they pass through the same point.

occurs when the opposite parts of two waves meet - results in the cancellation of the two waves.

Dark fringes

occurs when identical parts of two waves meet. - results in a new wave with the same wavelength but twice the amplitude.. right fringes