Tides / Eclipses / Phases of the Moon

Moon Phase Misconceptions Moon Phases

Phases of the Moon The moon moves through space two ways Rotates on its axis (27.3 Earth days for one rotation) Revolves around the Earth (27.3 Earth days for one revolution) A “day” and a “year” are the same length on the moon

Lunar Cycle The time between two full moons is called a lunar cycle A lunar cycle is 29.5 Earth days In other words there are 29. 5 days between full moons

Phases of the Moon Like the Earth – half of the moon is always in sunlight The different shapes of the moon we see are called phases The phase of the moon we see depends on how much of the sunlit side of the moon faces Earth

Waxing and Waning Waxing – when the portion of the moon you can see is growing Waning – when the portion of the moon you can see is shrinking Copy trick in notes

New Moon No Moon Visible

Crescent Moon is less than half lit

1st Quarter / 3rd Quarter Moon is half lit

Gibbous More than half lit but not full

Full Moon Entire moon disk visible

Eclipse Eclipse - The partial or total blocking of one object in space by another Moon’s shadow will hit the Earth or the Earth’s shadow will hit the moon Parts of a shadow Umbra – the darkest part of a shadow Penumbra – the larger (not as dark) part of a shadow

Lunar Eclipse Lunar Eclipse Earth blocks sunlight from reaching the moon Earth’s shadow is cast on the moon Occurs only during a full moon

Solar Eclipse Moon passes between the Earth and Sun Blocks sunlight from hitting Earth – Moon’s shadow hits Earth Occurs only during a new moon

Eclipse Why don’t we have an eclipse every month? The moon’s orbit around Earth is tilted at 5° This keeps the moon out of Earth’s shadow most of the time

Eclipses Lunar Eclipse

Eclipses Solar Eclipse

Earth’s Tides Tides The periodic rise and fall of large bodies of water Produced by the gravitational forces of the moon (and to a lesser extent the sun)

Lunar Tides – How do they work? Earth and Moon are attracted to each by the force of gravity The moon pulls on everything on the Earth’s surface Earth can hold everything in place except water

Lunar Tides The gravitational attraction of the moon causes the oceans to bulge out in the direction of the moon

Lunar Tides Another bulge happens on the opposite side of Earth Why? Because the Earth is being pulled towards the moon and away from the water on the far side Each day there are 2 High tides and 2 Low Tides 12.5 hours between two high tides

Types of tides Spring tides They have NOTHING to do with the season spring Occur when the moon is full or new and in line with the sun High tides are very high Low tides are very low

Types of Tides Neap tides Occur during a moons quarter phases Sun and moon are at right angles (90°) Cause ocean bulges to cancel each other out Very weak tides

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