Actually, the Sun and the stars do not move around us! The Earth is the one moving around the Sun. Similarly, the Earth has an axis but it is not straight up. This is because the Earth is not spinning upright. The Earth is slightly tilted or leaning on its side by Sunlight falls only on one side of the Earth.
This side of the planet will be experiencing daylight. Because the Earth is rotating, the opposite side of the Earth away from the Sun will be experiencing night. After some time, the part of the Earth experiencing daylight will experience night. Rotation of the Earth causes night and day to alternate. Different places in the Earth experiences different lengths of night and day. The 12 hours of day and 12 hours of night happens only in places near the equator, for example the Philippines.
Arctic and Antarctic experience polar day when the Sun stays above the horizon for more than 24 hours and polar night when night lasts for more than 24 hours. The styrofoam ball represents the Earth. Draw the outlines of the continents on the styrofoam using a pencil.
You will use the globe model shown by your teacher or the map of the globe on the projector as drawing guides.
The drawing does not need to be detailed. Just make sure to draw the Philippines clearly. Include also Brazil which is on the opposite side of the Philippines. Mars has a day and night cycle similar to Earth. Mars rotates on its axis once every Venus turns once on its axis every Earth days which is only slightly longer than it takes for Venus to go around the Sun!
Mercury's day and night cycle is more complex. Mercury rotates one-and-a-half times during each orbit around the Sun. Because of this, Mercury's day — from sunrise to sunrise — is Earth days long. The larger planets spin much faster. Jupiter rotates once every 10 hours, Saturn spins once every 11 hours, and Neptune completes a rotation in 16 hours.
Pluto, at the farthest reaches of our solar system, spins on its axis once every 6. Pluto is so distant from the center of our solar system that our Sun would look like a very bright star in its sky! Why does Earth's day length change during the year? Every location on Earth experiences an average of 12 hours of light per day but the actual number of hours of daylight on any particular day of the year varies from place to place.
Locations around Earth's equator only receive about 12 hours of light each day. In contrast, the north pole receives 24 hours of daylight for a few months in the summer and total darkness for months in the winter. These two annual times of light and dark are separated by a long sunrise and a long sunset.
Earth rotates on its axis; this causes us to experience day and night. But Earth's axis is tilted As Earth orbits our Sun, the axis points toward the same location in space — almost directly toward Polaris, the North Star. The actual time of one Earth rotation is a little shorter — about 23 hours and 56 minutes.
Astronomers discovered this by observing the time it took for a star to appear in the same place in the sky the following day, and they called this a sidereal day. Although a solar day is 24 hours, not every day has 12 hours of daylight and 12 hours of night. Daytime is shorter in winter than in summer.
As the Earth moves around the sun during a year, the northern half of the Earth is tilted towards the sun in the summer, making daytime longer than night.
In winter, this reverses; the earth tilts away from the sun and nighttime becomes longer. In the spring and fall, the tilt is neither toward or away from the sun but somewhere between, so day and night are more the same at these times of the year.
The solstices are the positions of the Earth's orbit that mark the longest and shortest days of the year. The winter solstice in the Northern Hemisphere is the shortest day, after which daylight hours grow longer. The summer solstice in the Northern Hemisphere falls on the longest day, after which daylight hours become shorter. The solstices can also be named for the month in which they occur. For example, the June solstice is the point in the Earth's orbit where the North Pole faces the sun.
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