Effects of the Earth, Sun, and Moon on the Calendar, Time Zones and Seasons

The Calendar Days

Based on the Earth’s rotation on its axis. When Earth rotates once all the way around on its axis, that’s a day.

The Calendar Months

Based on the Moon’s revolution around the Earth, when the moon makes one complete trip around the earth, that’s 1 ______

The Calendar Years

Based on the Earth’s revolution around the sun.

Time Zones

No matter where you are on Earth, when the sun is directly overhead, we call that the ZEITH POINT, means it’s 12 Noon

**If you get a Q aw/ time zones, sometimes you can’t read the label of the Time Zones themselves, but just understand concept of them

Time Zones More

Every zone is 1 hour.

Going west, time gets earlier

Going east, time gets later

Each line = one hour

e.g. Liam lives in New York (Eastern Time Zone), and his friend Ava lives in Denver (Mountain Time Zone). If Liam calls Ava at 5:00 PM his time, what time is it for Ava in Denver?

Reason we have Seasons

The orientation of that tilt changes

So if this is the sun,

and this is the Earth tilting,

that tilt basically stays the same,

but as you come around,

the Northern Hemisphere is now pointed more directly towards the sun

As it continues moving the other way,

now Northern Hemisphere is pointed away from the Sun.

Pointed away= Winter in the North

Point towards= Summer in the North

Seasons (simple terms)

The Earth is tilted as it spins.

As it moves around the Sun, this tilt makes different parts of the Earth get more sunlight at different times of the year.

This is why we have seasons!

The Earth’s tilt changes a tiny bit, but that doesn’t really affect the seasons.

The Earth doesn’t move much closer or farther from the Sun, and even though its path is a little stretched out (not a perfect circle), that’s not what causes seasons.

Winter and Summer Solstice

On the day it’s pointed most directly away from the sun in the North, and most directly towards the Sun in the South,

North is having it’s Winter Solstice and Southern Hemisphere is having it’s Summer Solstice

On the day when the top half of the Earth (North) is tilted farthest away from the Sun, the bottom half (South) is tilted closest to the Sun.

This means the North is having its Winter Solstice (the shortest day of the year), and the South is having its Summer Solstice (the longest day of the year)!

Summer Solstice

Longest day of the year

Winter Solistice

Shortest day of the year/ longest night

Equinox= Equal Night

• This happens when the Earth is not tilted toward or away from the Sun. Instead, it's perpendicular (straight up and down) compared to the Sun.

• Tilt becomes less relevant when positioned straight rather than pointing away or toward

• Because of this, both halves of the Earth (the Northern and Southern Hemispheres) receive the same amount of sunlight.

• Day and night are nearly equal in length (the amount of day and night and solar exposure both hemispheres are getting) all over the world. That’s why it’s called the Equinox!

Vernal (Spring) Equinox

and

Autumnal (Fall) Equinox

When Northern Hemisphere is having Vernal Equinox, the Southern Hemisphere is having the Autumnal Equinox

• Earth would continue around

• now the Northern Hemisphere points towards Sun, it has it’s summer solistice,

• on corresponding day, the Southern Hemisphere has its Winter Solistice

Then is switches

• When the Northern Hemisphere has its Spring (Vernal) Equinox, the Southern Hemisphere is having its Fall (Autumnal) Equinox.

• As Earth keeps moving around the Sun, the Northern Hemisphere starts tilting toward the Sun. This brings Summer Solstice in the North.

• On that same day, the Southern Hemisphere is tilted away from the Sun, so it's having its Winter Solstice.

• Then, it switches! As Earth keeps orbiting, the North will tilt away for winter, and the South will tilt toward the Sun for summer.

Seasons Isn’t About Tilt, Rather

how the tilt is positioned as Earth moves around the Sun.

• The tilt never changes, but as Earth orbits, it faces different directions in space.

• Sometimes, the Northern Hemisphere is tilted toward the Sun (summer), and sometimes it’s tilted away (winter).

• The Southern Hemisphere is opposite—when the North has summer, the South has winter, and vice versa.

So, seasons happen because of the direction the tilt is facing, not because the tilt itself changes!