Earth

Equator

0 degrees An imaginary line dividing the Earth into the Northern and Southern Hemispheres.

Tropic of Cancer

23.5 degrees North The sun is directly overhead on December 21st.

Tropic of Capricorn

23.5 degrees South The sun is directly overhead on June 21st.

Arctic Circle

66.5 degrees North The Arctic Circle receives 24 hours of sunlight on June 21st and 0 hours of daylight on December 21st.

Antarctic Circle

66.5 degrees South Receives 24 hours of daylight on December 21st and 0 hours of daylight on June 21st.

What is a leap year? Why do we have leap years?

A leap year is an extra day added to February. It happens every 4 years. When all the 1/4 days add up, that adds one day. That day is February 29th on our calendar.

season

A major division in the year. The weather changes.

axis

An imaginary line that goes through the center of the Earth.

Latitude

Distance north or south of the equator.

Rotation

Earth rotates every 24 hours. Earth rotates counter-clockwise. Rotation is Earth spinning on its axis. Rotation causes Earth to have day and night.

revolution

Earth takes 365 1/4 days to compete an entire revolution. A revolution is the movement of Earth in its orbit around the sun. Revolutions cause the Earth to have seasons.

Vernal Equinox

First day of spring. Occurs on March 21st. There is 12 hours of daylight everywhere.

Northern Hemisphere

Half a sphere above the equator. Seasons are opposite the Southern Hemisphere.

Southern Hemisphere

Half a sphere below the equator. Seasons are the opposite of the Northern Hemisphere.

What season is occurring in the Northern and Southern hemisphere due to the tilt of the Earth?

If the Northern Axis is facing away from the sun, in the Northern Hemisphere it is winter. In the Southern Hemisphere it is summer. If the Northern axis is facing toward the sun in the Northern Hemisphere it is winter and in the Southern Hemisphere it is summer.

How long does it take the Earth to revolve? What does it cause?

It takes Earth 365 1/4 days for Earth to revolve once. This causes a year.

What causes seasons? (2 things)

Seasons are caused by Earth's tilted axis and Earth revolving around the sun.

How long does it take Earth to rotate? What does it cause?

The Earth takes 24 hours (1 day) to rotate once. Earth rotating causes day and night.

Autumnal Equinox

The first day of fall. It occurs on September 21st. There is 12 hours of daylight everywhere.

How does the tilt of the Earth affect the length of daylight hours in a day? How does it cause direct and indirect sunlight?

When the Earth is tilted toward the sun, the days are longer. When Earth is tilted toward the sun, the Earth is getting direct light on the Tropic of Cancer. It is the opposite of Earth being tilted away from the sun.

Polaris

the North Star. Earth's axis is tilted toward it.

Summer Solstice

the first day of summer. In the Northern Hemisphere it is on June 21st. The sun is directly overhead at 23.5 degrees North, at the Tropic of Cancer. It is the longest day of the year.

Winter Solstice

the first day of winter. It falls on December 21st. The sun is directly overhead at 23.5 degrees South, the Tropic of Capricorn. It is the shortest day of the year.

orbit

the path of Earth's movement around the sun.