Science 9 unit E 1.1-4.3

Solstice

Longest/shortest day of the year

Shortest day of solstice

Winter solstice (dec 21; first day of winter)

Longest day of solstice

Summer solstice (June 21; first day of summer)

Equinox

2 days of the year with equal amounts of night and day

Spring equinox

March 21, first day of spring

Fall equinox

Sept 21, first day of fall

Geocentric model (3 things)

• idea by Aristotle 2000 years ago

• Earth is centre of solar system

• Everything orbits earth in solar system

Heliocentric model (4 things)

• Idea by Copernicus 1530

• Sun is centre of solar system

• Everything orbits sun in sphere pattern

• Supported by Galileo 1600

Ellipses

Oval shape, the way our planets orbit sun

Quadrant

Measures a stars height above the horizon

Astrolabe

Used to make charts of star positions

Cross-staff

Measures angle between the moon and any given star AKA Jacob’s staff

Early telescope

First invented in late 16th century

Sundial

Measures time by position of sun

Merkht

Charts astronomical positions and predicts movement of stars

Spectroscope

Breaks down light into spectrum colors

Astronomical units AUs (2 things)

• used for local distances (inside our solar system)

• 1 AU is equal to the distance from the center of the earth to the center of the sun

Light years (2 things)

• Used for distance beyond our solar system (other stars or galaxies)

• Equal to distance that light travels in one year. Light travels at 300 000km/s in one year that adds up to 9.5 billion km