Moon Phases, Tides, and Eclipses Flashcards

A set of vocabulary flashcards covering the Earth-Sun-Moon system, including moon phases, tidal variations, and the mechanics of solar and lunar eclipses.

Phases of the Moon

The different shapes of the lit portion of the moon as seen from Earth throughout the month.

Moon's Light Source

The moon does not produce its own light; it is reflected sunlight.

Visible Side of the Moon

The phenomenon where only one side of the moon ever faces Earth, despite only half of the moon being lit by the sun at any time.

Lunar Phases

The specific pattern and sequence of the moon's appearance as it moves through its orbit around Earth.

Waxing

The period during the moon's orbit when the visible lit surface is increasing in size.

Waning

The period during the moon's orbit when the visible lit surface is decreasing in size.

Crescent

A moon phase where less than half of the side facing Earth is illuminated.

Gibbous

A moon phase where more than half of the side facing Earth is illuminated.

Tides

The periodic rise and fall of Earth's ocean levels caused by the gravitational pull of the moon.

Spring Tide

A tide with the greatest difference between high and low water that occurs when the moon is in specific locations in its orbit (aligned with the sun).

Neap Tide

A tide with the least difference between high and low water based on the moon's location in its orbit.

Umbra

The darkest, cone-shaped part of a shadow where the light source is completely blocked.

Penumbra

The lighter portion of a shadow where the light source is only partially blocked.

Eclipse

An event where one celestial object casts a shadow on another.

Lunar Eclipse

An event occurring during a full moon phase where Earth's shadow is cast upon the moon.

Total Lunar Eclipse

An event where the entire moon passes into the umbra, often causing the moon to turn red.

Solar Eclipse

An event occurring during a new moon phase where the moon passes between the sun and Earth, casting a shadow on Earth.

Earth’s Orbital Plane Tilt

The reason why solar and lunar eclipses do not occur every month, due to the specific degree of tilt in the moon's orbit relative to Earth.

Apparent Size

The visual size relationship between the moon and the sun as seen from Earth, which is affected by the distance between the Earth, moon, and sun.