Gibson, Everett » Unit 4: Earth, Moon, and Sun Overview

Unit 4: Earth, Moon, and Sun Overview

Revolution

The motion of a body that travels around another body in space

Year

The time it takes for a planet to complete one revolution around a star

Rotation

The spinning of a planet on its axis

Axis

The imaginary line that passes through the center of a planet from pole to pole

Day

The time it takes a planet to complete one full rotation on its axis

Season

One of four parts of the year marked by changes in hours of daylight and changes in weather

Northern Hemisphere

The region of the earth from the equator to the North Pole

Summer Solstice

The time of the year in which the longest day occurs

Winter Solstice

The time of the year in which the shortest day occurs

Equinox

The time at which the sun is directly overhead at the equator causing day and night to be about equal lengths

Lunar phase

The gradual change in the appearance of the Moon due to the positions of Earth, the Moon, and the Sun

Lunar eclipse

An event that occurs when the Earth’s shadow falls on the Moon

Solar eclipse

An event that occurs when the Moon’s shadow falls on the Earth

Umbra

The darkest part of a shadow

Penumbra

The lighter part of a shadow
 

New Moon

The Moon is not visible. The side that is facing away from Earth is lit and the side facing Earth is not lit

Waxing Crescent

The Moon appears to be less than half lit by sunlight. The lit fraction of the Moon is increasing each day

First Quarter

The right half of the Moon appears lit and the left side of the Moon appears dark

Waxing Gibbous

The Moon appears to be more than half, but not fully, lit by sunlight. The lit portion will grow larger every day

Full Moon

The Moon appears to be completely lit by sunlight.  The lit side of the Moon faces the Earth

Waning Gibbous

The Moon appears to be more than half, but not fully, lit by sunlight. The lit portion will grow smaller every day

Last Quarter/Third Quarter

The left half of the Moon appears lit, and the right side of the Moon appears dark

Waning Crescent

The Moon appears to be less than half lit by sunlight.  The lit fraction of the Moon is decreasing each day

Tide

A cycle of rising and falling ocean levels

Tidal Range

The difference between the levels of ocean water at high tide and low tide

Spring Tide

When the tidal range is at is largest and the tides are unusually high and low on the same day

Neap Tide

When the tidal range is at its smallest