Chapter 10 Earth, Sun, & Moon 6 th Grade

Section 1 0 Earth’s axis: an imaginary line that runs through Earth’s center from the north pole to the south pole. Earth rotates on its axis and revolves around the sun-- -revolution. 0 One revolution is 365 and ¼ days. And one rotation is 23 hours and 56 minutes. 0 One day is 24 hours not just the time sun is shining. Because Earth turns counterclockwise the sun rises in the east and sets in the west.

Section 1 0 Summer in Tennessee: Earth’s tilt is positioned so that the Northern Hemisphere points towards the sun and Southern Hemisphere points away. So, Northern Hemisphere receives more direct solar energy. 0 During winter Northern Hemisphere points away from sun while Southern Hemisphere points toward the sun. 0 Earth’s tilt is 23.5 degrees.

Section 1 0 Equinoxes: neither end of Earth’s axis is tilted toward the sun. So both hemispheres receive the same amount of solar energy. 0 Solstices: When the sun is farthest North or South of the equator. 0 However, the closer to the equator one lives the less seasonal change they will experience.

Section 1 0 March Equinox (March 21):The daylight hours equals the number of nighttime hours all over the world. 0 June Solstice (June 22) The North Pole is tilted toward the sun. This marks the beginning of summer in the Northern Hemisphere. 0 September Equinox (September 23): Marks the beginning of fall for the Northern Hemisphere. Neither the Southern nor Northern Hemisphere is tilted more towards the Sun. 0 December Solstice (December 22): North Pole is tilted away from the sun. Marks the beginning of winter for Northern Hemisphere.

Section 2 0 Every 27.3 days the moon rotates once on its axis and revolves once around the Earth. Rotates and revolves at the same speed so the same side of the moon is always facing earth. However, it completes it lunar cycle in 29.5 days. 0 Moon Phases: The amount of sunlight reflected toward the Earth by the face of the moon causes different phases. 0 Waxing: The sunlit part that can be seen from Earth appears to get larger. 0 Waning: The sunlit part seems to get smaller You need to know all of the phases of the moon on page 295! EB EB

Section 2 0 Lunar Eclipse: happens when the Earth is between the sun and the moon and Earth’s shadow falls on the moon. Has to be a full moon. 0 Solar Eclipse: happens when the moon is between Earth and the sun and the moon’s shadow falls on Earth. Has to be a new moon. 0 Lunar and Solar Eclipses do not happen every month because the moon’s orbit around the Earth is tilted by about 5 degrees in relation to Earth’s orbit around the sun.

Section 2 0 Annular Solar Eclipse: The moon does not fully cover the disk of the sun. Some of the sun shows around the edges of the moon. Moon is farther from Earth. 0 Total Solar Eclipse: Moon is closer to Earth and appears the same size as the sun. It fully covers the sun. Only the corona is visible---suns atmosphere. 0 Lunar eclipses can only happen during full moons.

Section 3 0 The movement of the Earth, sun, and moon affects the movement of oceans. 0 Tides are influenced by gravity. Gravity of the moon pulls on every particle of the Earth. Liquids move easier than solids so the pull is more noticeable. 0 The moon’s pull is strongest on the part of Earth that is directly facing the moon. 0 The part that is facing the moon causes the water to bulge toward the moon as does water on the opposite side. The bulges are called high tides. These high tides cause low tides in other places.

Section 3 0 Tides are determined by Earth’s rotation and by the moons revolution around the Earth. 0 Sun also affects tides. Its influence is less than the moon’s. 0 Tidal Range: the difference between the level of ocean water at high tide and the level at low tide.

Section 3 0 Spring Tides: when the sun, earth, and moon are aligned. These tides have the largest daily tidal range and occur during the new and full moons---every 14 days. 0 Neap Tides: When the sun, earth, and moon form a 90 degree angle. These have the smallest daily tidal range and occur during the first and third quarters of the moon. The gravitational forces of the sun and moon work against each other.