Name: Earth and Space Assessment Study Guide. Assessment Date : Term Rotation Revolution

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1 Name: Earth and Space Assessment Study Guide Assessment Date : Earth s Rotation and Revolution Term Rotation Revolution Brief Definition Earth s Time to Complete One complete spin on an axis 24 hours (or 1 day) One complete orbit, or path, around another object 365 ¼ days Causes Day and Night Seasons Graphic Impact on Shadows When the sun is low on the horizon (like sunrise or sunset), shadows will be long and falling to the opposite direction of the sun. *Low = Long* When the sun is high in the sky (at midday), shadows will be short and directly below objects. *High in Sky = Short* In the winter, we receive indirect rays of sunlight during the day, in other words sunlight shines at an angle. The sun is lower on the horizon so shadows are longer at midday than other times of the year. In summer, we receive direct rays of sunlight, so the sun will be very high in the sky at midday, creating short shadows.

2 Seasons The Northern Hemisphere (above the equator) is getting less direct rays of sunlight in December so it is WINTER! At the same time, the Southern Hemisphere is getting more direct rays, so it is SUMMER! The Northern Hemisphere (above the equator) is getting more direct rays of sunlight in June so it is SUMMER in the Northern Hemisphere! The Southern Hemisphere is getting indirect rays, so it is WINTER. Gravity The gravitational force exerted (or applied) by Earth on objects is directed toward Earth s center. We know this because people living on the other side of the Earth do not fall off! We are all pulled to the ground (toward the center of the Earth) no matter where we live. The Earth s gravity tries to pull the moon towards itself. The Moon s inertia tries to propel its movement forward in a straight line. The compromise is that both gravity and inertia keep the Moon in orbit around the Earth.

3 Moon In the above picture, the small circle of moons around the Earth shows the moon s revolution around the Earth. The larger circle of moons show what the moon would look like from Earth based on where it is in the revolution. The shape of the moon looks different because of its position in relation to the Earth and the Sun. Phase the appearance and shape of the moon as you see it from Earth REMEMBER! The Moon does not create its own light. Like planets, the Moon is bright in our night sky because of the sun s light. A solar eclipse is when the moon s shadow falls on the earth. A lunar eclipse is when the earth s shadow covers the moon.

4 Planets The below list shows the order of the planets in relation to the distance the planet is from the sun. Mercury is the closet planet while Neptune is the furthest planet. Sun Remember this silly phrase to be reminded of the order of the planets! The first letters match the planet s first letters, in order: My Very Educated Mother Just Served Us Nachos The Sun in our solar system is a star. It is the CLOSEST star to us. This is why the Sun appears to be the biggest and brightest star. The Sun gives us daylight hours it is so bright! Our Sun appears to be the biggest and brightest star BUT IT IS NOT REALLY THE BIGGEST OR BRIGHTEST STAR IN THE GALAXY! There are much bigger and brighter stars in the galaxy, our Sun is just an average-sized star. So distance is a HUGE factor for how bright a star appears from Earth. Stars and Constellations Since we are revolving around the Sun, we will see different constellations in the night sky. The constellations change with the seasons!

5 Reference - Important Vocabulary Gravity- The force of attraction or pull between any two objects. The strength of the pull of gravity depends on the mass of the objects and the distance between the objects. Inertia- the tendency of a moving object to keep moving in a straight line Orbit- the path one object takes around another Revolution- one complete trip (or orbit) around the sun, Earth makes this trip in 365 ¼ days. Rotation- one complete spin on the axis, Earth makes one rotation every 24 hours. Axis- imaginary line that Earth is rotating on; goes through the center of the Earth Equator- imaginary line that goes around the middle of the Earth and divides the northern and southern hemispheres Northern Hemisphere- the top half of the Earth that includes the North Pole, North America, Europe, and Russia Southern Hemisphere- the bottom half of the Earth that includes the South Pole, South America, and Australia Phase- the appearance and shape of the moon as you see it, the phase of the moon depends on the location of the Moon in relation to the Earth and the Sun. Waxing- the visible part of the moon is getting bigger (the moon appears to be getting bigger) Waning- the visible part of the moon is getting smaller (the moon appears to be getting smaller) Gibbous- when the observable illuminated part of an object in space (like the moon) is greater than a semicircle and less than a circle Crescent- how the moon (or another object in space) appears early in its first quarter or late in its last quarter, when only a small arc-shaped section of the visible portion is illuminated by the Sun

6 Solar eclipse- occurs when the Moon passes directly between Sun and the Earth (Moon casts a shadow on Earth) Lunar eclipse- occurs when Earth is between the sun and the Moon (Moon moves into Earth s shadow and is no longer reached by direct sunlight). Tide- the rise and fall of the ocean s surface, the pull of gravity causes ocean water to bulge on the side of Earth facing the moon, a matching bulge occurs on the side of Earth that is opposite the moon. Planet- a large object in space moving in an elliptical orbit around a star; planets are spheres, shaped like a ball Star- an object that produces its own heat and light energy Constellation- patterns of stars, often named after animals or mythological figures; helped with navigation and mapping the sky Light year- the distance light travels in one year (about 5.9 billion miles). Astronomical Unit (AU)- unit of measurement equal to about 93 million miles; this measurement is used to measure distances in our solar system Galaxy- a system of millions or billions of stars, together with gas and dust, held together by gravitational attraction; our solar system is a part of the Milky Way Galaxy.