Notes - Notes - Moon, Tides, & SeasonsMoon, Tides, & Seasons

Earth in SpaceEarth in Space

The Earth spins on an imaginary The Earth spins on an imaginary line called the axis that passes line called the axis that passes from the North Pole to the South from the North Pole to the South Pole.Pole.

The spinning of Earth on its axis The spinning of Earth on its axis is called rotation, and this causes is called rotation, and this causes day and night.day and night.

It takes Earth about 24 hours to It takes Earth about 24 hours to rotate once.rotate once.

Earth in SpaceEarth in Space Earth orbiting around the Sun is called Earth orbiting around the Sun is called

revolution.revolution. Earth completes one revolution every 365 ¼ Earth completes one revolution every 365 ¼

days or 12 moon cycles.days or 12 moon cycles. Earth’s orbit is a slightly flattened circle, and it Earth’s orbit is a slightly flattened circle, and it

varies every 100,000 years in shape.varies every 100,000 years in shape.

Earth in SpaceEarth in Space

The Reason for the SeasonThe Reason for the Season Earth has seasons because its Earth has seasons because its

axis is tilted 23.5º away from the axis is tilted 23.5º away from the Sun for half the year, and toward Sun for half the year, and toward the Sun for the other half.the Sun for the other half.

The Reason for the SeasonThe Reason for the Season When the North pole is tilted toward the Sun, When the North pole is tilted toward the Sun,

the Northern hemisphere has summer (June, the Northern hemisphere has summer (June, July, & August). During these months the July, & August). During these months the Southern hemisphere has winter because they Southern hemisphere has winter because they are tilted away from the Sun.are tilted away from the Sun.

The Reason for the SeasonThe Reason for the Season

The Reason for the SeasonThe Reason for the SeasonTwo days a year, the Two days a year, the

noon sun is directly noon sun is directly overhead at 23.5º overhead at 23.5º North or South – North or South – solstice days.solstice days.

Halfway between Halfway between solstice days, at noon solstice days, at noon the sun is directly the sun is directly overhead at the overhead at the equator – equinox equator – equinox days (equal day & days (equal day & equal night).equal night).

Motions of the MoonMotions of the Moon

The moon is about ¼ the diameter of The moon is about ¼ the diameter of EarthEarth

The moon revolves around Earth about The moon revolves around Earth about once every once every 27.3 days27.3 days

The The samesame side of the moon always faces side of the moon always faces EarthEarth

Phases of the MoonPhases of the Moon

Different shapes we Different shapes we see are the phases of see are the phases of the moon the moon

The phase depends The phase depends on how much of the on how much of the sunlit side of the sunlit side of the moon faces Earthmoon faces Earth

Phases of the MoonPhases of the Moon From new moon to full moon, you see an From new moon to full moon, you see an

increasing amount of the lighted sideincreasing amount of the lighted side

1.1. NewNew

2.2. First Quarter (right half lit up)First Quarter (right half lit up)

3.3. FullFull

4.4. Third Quarter (left half lit up)Third Quarter (left half lit up)

new first quarter full third / last quarter

EclipsesEclipses

Eclipses happenEclipses happen1.1. when the moon’s shadow hits Earthwhen the moon’s shadow hits Earth

2.2. when Earth’s shadow hits the moonwhen Earth’s shadow hits the moon Eclipses happen when an object in Eclipses happen when an object in

space comes between the sun and a 3space comes between the sun and a 3rdrd object, and casts a shadow on that object, and casts a shadow on that objectobject

Moon passes between Earth & the sunMoon passes between Earth & the sunThe moon’s shadow hits EarthThe moon’s shadow hits EarthUmbra = darkest part of the moon’s Umbra = darkest part of the moon’s

shadow (only people who live in the umbra shadow (only people who live in the umbra see a total solar eclipse)see a total solar eclipse)

Penumbra = less dark, but larger shadow Penumbra = less dark, but larger shadow (people who live here see a partial eclipse)(people who live here see a partial eclipse)

Solar Eclipses (SUN is blocked)Solar Eclipses (SUN is blocked)

Solar EclipsesSolar Eclipses

Lunar Eclipse (MOON is blocked)Lunar Eclipse (MOON is blocked)

Occurs at a full moon when Earth is Occurs at a full moon when Earth is directly between the moon & sundirectly between the moon & sun

Earth’s shadow falls on the moonEarth’s shadow falls on the moonEarth’s shadow has an umbra & penumbraEarth’s shadow has an umbra & penumbra

Lunar EclipseLunar Eclipse

TidesTides

Rise & fall of the ocean’s water every 12.5 Rise & fall of the ocean’s water every 12.5 hourshours

Gravity pulls the moon and Earth toward Gravity pulls the moon and Earth toward each othereach other

Tides occur because of how much the Tides occur because of how much the moon pulls on different parts of Earthmoon pulls on different parts of Earth

TidesTides

Earth rotates & the moon’s Earth rotates & the moon’s gravity pulls water toward the gravity pulls water toward the point on Earth’s surface point on Earth’s surface closest to the moonclosest to the moon

The moon pulls least on the The moon pulls least on the side of Earth farthest awayside of Earth farthest away

2 high tides a day & 2 low tides 2 high tides a day & 2 low tides a daya day

Spring TidesSpring Tides

Twice a month: the moon, Twice a month: the moon, Earth, & the sun are in a Earth, & the sun are in a straight line, creating more straight line, creating more gravitygravity

HIGH high tide & LOW low HIGH high tide & LOW low tidetide

Called this because the water Called this because the water “springs” up & down the “springs” up & down the beachbeach

Neap TidesNeap Tides

Twice a month: the moon, Earth, & Twice a month: the moon, Earth, & the sun are at right angles to each the sun are at right angles to each otherother

LOW high tide & HIGH low tideLOW high tide & HIGH low tide

Spring & Neap TidesSpring & Neap Tides

1. The phase of the moon you see depends on

A how much of the sunlit side of the moon faces Earth

B where you are on Earth’s surface

C how much of the moon’s surface is lit by the sun

D whether or not an eclipse is occurring

3.2 Pressure and the Buoyant Forces

2. From new moon phase to full moon phase you see

A a decreasing amount of the lighted side of the moon

B an increasing amount of the lighted side of the moon

C the same amount of the lighted side of the moon.

D more of the lighted side, then less of the lighted side of the moon.

3.2 Pressure and the Buoyant Forces

3. For a solar eclipse to occur,

A the sun must be directly between the Earth and the moon.

B the moon must be directly behind Earth.

C the moon must be directly between the Earth and the sun.

D Earth must be directly between the sun and the moon.

3.2 Pressure and the Buoyant Forces

4. During what phase can a lunar eclipse occur?

A first quarter

B full moon

C third quarter

D new moon

3.2 Pressure and the Buoyant Forces

5. When are tides highest?

A when the sun, Earth, and the moon are nearly in a line

B during the moon’s first quarter phase

C during the moon’s third quarter phase

D when the moon is at a right angle to the sun

3.2 Pressure and the Buoyant Forces

6. Tides are caused mainly by

A Earth’s rotation on its axis, which causes water to move

B differences in how much the sun pulls on different parts of Earth

C differences in how much the moon pulls on different parts of Earth

D strong winds blowing water onto coasts

3.2 Pressure and the Buoyant Forces

7. How large is the moon compared to Earth?

A about the same diameter as Earth

B about 1/8 the diameter of Earth

C about 1/4 the diameter of Earth

D about 1/2 the diameter of Earth

3.2 Pressure and the Buoyant Forces

8. The amount of the lighted side of the moon you can see is the same during

A first quarter and third quarter phase

B new moon and full moon phase

C new moon and first quarter phase

D full moon and third quarter phase

3.2 Pressure and the Buoyant Forces

9. When do neap tides occur?

A at new moon

B when the sun’s pull is in the same direction as the moon’s

C at full moon

D when the sun’s pull is at right angles to the moon’s

3.2 Pressure and the Buoyant Forces

10. Earth’s axis is tilted ___.

A 22º

B 22.5º

C 23.5º

D 24º

3.2 Pressure and the Buoyant Forces

11. When the North pole is tilted toward the sun, the Northern hemisphere has

A winter

B spring

C summer

D fall

3.2 Pressure and the Buoyant Forces