Summer happens in the hemisphere tilted towards the Sun, and winter happens in the hemisphere tilted away from the Sun.
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Earth's Tilt Is the Reason for the Seasons!
The Earth travels around the Sun one full time per
year. During the year, the seasons change depending on the amount of sunlight
reaching parts of the Earth.
The seasons are caused because the Earth is tilted
23.5 degrees on its axis. Summer happens to the hemisphere tilted towards the
Sun, and winter happens to the hemisphere tilted away from the Sun. The hemisphere
that is tilted towards the Sun is warmer because sunlight travels more directly
to the Earth’s surface so less gets scattered in the atmosphere. That
means that when it is summer in the Northern Hemisphere, it is winter in the
Southern Hemisphere. The hemisphere experiencing summer, tilted towards the
Sun, has longer days and shorter nights than the hemisphere tilted away from
- On June 21st, the Northern Hemisphere is having its summer
solstice because it is tilted towards the Sun receiving the most direct
sunlight of the year during the longest day. The Southern Hemisphere is having
its winter solstice, the shortest day of the year, because it is tilted away
from the Sun.
- On December 21st, the Southern Hemisphere is tilted towards the Sun receiving
the most direct sunlight of the year during the longest day. The Northern
Hemisphere is having its winter solistice,
tipped away from the Sun, producing the shortest day of the year and a low
In general, summer and winter temperatures get lower the further you travel
from the equator. At the equator, there are no seasons because each day the
Sun strikes at about the same angle. Every day of the year the equator receives
about 12 hours of sunlight. The poles remain cool because they are never tilted
in the direct path of the sunlight. Light must travel through so much atmosphere
that much of it is scattered before reaching the Earth surface. During midwinter,
when a pole is tilted away from the Sun, there is no daylight at all at the
pole. The Sun never rises. However, during the summer, a pole receives sunlight
all the time and there is no night!
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The Winter 2009 issue of The Earth Scientist
, focuses on Earth System science, including articles on student inquiry, differentiated instruction, geomorphic concepts, the rock cycle, and much more!
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