17 Questions
Which BEST explains why the Earth is not disk-shaped?
The only shape that cast a circular shadow in whatever direction is a sphere.
Which of the following is an annual motion?
Vernal equinox
What astronomical event was NOT known to men before the advent of telescopes?
Retrograde of Mars
Which aided Eratosthenes in measuring the Earth's circumference?
The shadows cast within the Syene and Alexandria during the solstice.
Match the following statements with the appropriate laws of planetary motion:
Which describes the law of ellipse? = Law of Ellipse Which describes the law of harmony? = Law of Harmony Which describes the law of equal areas? = Law of Equal Areas Which explains the difference in the orbital period of Earth and Saturn? = Law of Harmony
Which attributes retrograde motion of the planets to epicycles?
Ptolemaic
Which states that a planet moves fastest when it is nearest to the sun?
Keplerian
Which BEST explains why the Earth is not disk-shaped?
The only shape that cast a circular shadow in whatever direction is a sphere.
Which of the following is an annual motion?
Vernal equinox
What astronomical event was NOT known to men before the advent of telescopes?
Rotation of the Sun
Which aided Eratosthenes in measuring the Earth's circumference?
The shadow cast within the Syene and Alexandria during the solstice.
What is a diurnal motion? The ________ motion is the apparent daily motion of stars and celestial bodies across the sky due to Earth's rotation.
diurnal
Which does NOT involve the Sun's ecliptic path? ________
Zodiac cycle
Match the following laws of planetary motion with their descriptions:
Law of ellipse = Any point in the closed curved is equidistant to the two foci. Law of harmony = Planets move fastest in the elliptical orbit when nearest to the sun. Law of equal areas = The length of a planet's revolution in the Sun is proportional to its orbit's size. Explanation of the difference in the orbital period of Earth and Saturn = All planets revolve around the sun in an elliptical orbit.
Match the following types of astronomical models with their descriptions:
Copernican = Presents a heliocentric model of the universe. Keplerian = Presents a system with elliptical orbit. Ptolemaic = Attributes retrograde motion of the planets to epicycles. Tychonic = Presents a geo-heliocentric model of the solar system.
HOW DID THE GREEKS KNOW THAT THE EARTH IS ROUND?
The Greeks inferred that the Earth is spherical based on observations, such as the circular shadow cast during a lunar eclipse and the different views of stars when traveling north and south.
WHAT WERE THE ASTRONOMICAL EVENTS KNOWN TO MEN BEFORE THE ADVENT OF TELESCOPES?
Before telescopes, humans knew about various astronomical events like solar eclipses, summer solstices, annual motions, equinoxes, and eclipses.
Study Notes
Models of the Universe
- The Greeks deduced that the Earth is spherical based on the observation that the shadow cast by the Earth during a lunar eclipse is circular and that the only shape that can cast a circular shadow at whatever direction is a sphere.
- Eratosthenes, a Greek Mathematician, measured the Earth's circumference by using the angles of shadows cast in two different cities during a solstice.
- The Earth's circumference is approximately 40,000 kilometers.
Astronomical Events Known to Men Before the Advent of Telescopes
- Ancient Babylonian, Assyrian, and Egyptian knew the length of the year and Egyptians adopted a calendar based on 365 days a year.
- The Egyptians also kept track of the yearly cycle of the star Sirius which corresponds to the flooding of Nile.
- Early Chinese civilizations kept track of the comets, meteors, and dark spots of the Sun.
- Mayan civilization developed a calendar based on the movements of Venus.
- The Polynesians utilized the stars for navigation.
Astronomical Events
- Diurnal motion: the apparent daily motion of stars and other celestial bodies across the sky due to Earth's rotation.
- Annual motion: the apparent yearly motion of stars and other celestial bodies across the sky due to Earth's revolution.
- Zodiac and the ecliptic: the path the sun takes in the celestial sphere, tracing the ecliptic, and a band of 13 constellations collectively called the zodiac.
- Equinoxes and solstices: the two days in a year in which the sun crosses the celestial equator, and the two days in a year in which the Sun is at the farthest declination from the celestial equator.
- Precession: the slow 'wobbling' of Earth's axis of rotation due to the gravitational pull of the Moon and Sun, resulting in a 26,000-year cycle.
- Eclipse: occurs when either the Earth or moon casts a shadow into each other, resulting in a solar or lunar eclipse.
Models of the Universe
- Ptolemy's model: the Earth is at the center of the universe, and the planets revolve around the Earth in an orbit called epicycle.
- Kepler's model: the Earth and other planets revolve around the Sun in elliptical orbits, with the Sun at one focus of the ellipse.
- Kepler's three laws of planetary motion:
- Law of Ellipse: orbits of all the planets are elliptical with the Sun at one focus of the ellipse.
- Law of Equal Areas: a line joining a planet and the Sun sweeps out equal areas in space in equal intervals of time.
- Law of Harmony: the square of a planet's orbital period is proportional to the cube of the semimajor axis of its orbit.
Notable Astronomers
- Tycho Brahe: a Danish astronomer who continuously and precisely recorded the position of the sun, moon, and planets for over 20 years.
- Johannes Kepler: a German mathematician and astronomer who analyzed Tycho Brahe's data and derived the three laws of planetary motion.
This quiz covers the module on models of the universe, from Greek astronomy to Kepler, for Grade 12 physical science students. It assesses their understanding of the historical development of astronomical models.
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