Seasons

Tilt

Leaning toward or away from another object. (Today, the Earth's axis is tilted 23.5 degrees from the plane of its orbit around the sun. But this tilt changes. During a cycle that averages about 40,000 years, the tilt of the axis varies between 22.1 and 24.5 degrees. Because this tilt changes, the seasons as we know them can become exaggerated.)

Equator

An imaginary line drawn around the earth equally distant from both poles, dividing the earth into northern and southern hemispheres and constituting the parallel of latitude 0°.

Axis

An imaginary line that passes through Earth's center and the North and South poles, about which Earth rotates. The Earth's axis points toward the North Star, at a 23.5-degree tilt to the plane of its orbit about the Sun.

Leap Years

Because the time it takes the Earth to orbit the Sun is about 365 1/4 days we add one day to the calendar every four years to make sure the seasons don't shift over time. We call the years with the extra day added to them ______.

Orbit (or revolution)

One celestial object moving around another.

23.5

The angle which the earth's axis is tilted.

Image of N.H. in summer

The image of the Northern Hemisphere is in which season?

Seasons

The result of the tilt of Earth's axis and the yearly revolution of the Earth around the sun.

Autumnal Equinox

The scientific way to say the day of the year that marks the beginning of fall in the Northern hemisphere

Vernal Equinox

The scientific way to say the day of the year that marks the beginning of spring in the northern hemisphere

Fall

The season experienced between Summer and Winter when the Earth's axis is neither tilted toward nor away from the Sun. The earth is in position 3 during this season in the Northern Hemisphere

Spring

The season experienced between Winter and Summer when the Earth's axis is neither tilted toward nor away from the Sun. The earth is in position 1 during this season in the Northern Hemisphere.

Spring and Fall

The seasons in which all locations on earth are receiving about the same amount of daylight hours

Rotation

The spinning of an object about it's own axis.

Summer

The summer season is experienced in the northern or southern hemisphere when the Earth is in that part of its orbit that the corresponding hemisphere is titled TOWARD the sun. The Earth is in position 2 during the Summer season in the Northern Hemisphere.

Winter

The winter season is experienced in the northern or southern hemisphere when the Earth is in that part of its orbit that the corresponding hemisphere is titled AWAY from the sun. The Earth is in position 4 during the Winter season in the Northern Hemisphere.

Winter Solstice

This occurs in December (around the 21st) and marks the beginning of winter in the Northern Hemisphere. This is the shortest day of the year in the Northern Hemisphere. The Northern Hemisphere is titled away from the Sun.

Summer Solstice

This occurs in June (around the 21st) and marks the beginning of summer in the Northern Hemisphere. This is also the longest day of the year in the Northern Hemisphere. The Northern Hemisphere is titled toward the Sun.

Spring equinox

This occurs in March and marks the beginning of spring in North America.

Fall equinox

This occurs in September and marks the beginning of fall in North America. Also called Autumnal equinox.

Equinox

Two times of year when the day and night lengths are about 12 hours. Equal day and night.

Solstice

Two times of year when the day or night lengths are at their longest or shortest. The northern hemisphere of the earth is either tilted towards or away from the sun at 23.5 degrees, while the southern hemisphere is titled in the opposite direction.

Image of N.H. in Winter

What does image 4 represent in the Northern Hemisphere?

Why are winter temperatures lower (cold)?

Winter occurs in either the Northern or Southern Hemisphere when the Earth is in that part of its orbit where, because of its tilted axis, that hemisphere receives less direct light from the Sun. The days are shorter, the Sun is lower in the sky, and the Sunlight's energy is less intense. This causes cooler temperatures in the corresponding hemisphere.

Hemisphere

half of a sphere