Astronomy Essential Questions and Answers: What is the force that pulls objects toward the center of the earth, between the earth and the moon and the earth and other planets? Students: Gravity is the force that pulls matter towards Earth and keeps us from floating off into outer space! Gravity exists in all things. Bigger things have more of it than smaller things, but it s only noticeable in gigantic things like moons, planets, and stars. Gravity affects how heavy objects are. Things on the moon would feel lighter than here on Earth because the moon has less gravity than Earth. Also, it s the Sun s gravity that keeps the planets from drifting off into outer space! Teachers: Sir Isaac Newton, English scientist, 1642-1727, explored the effect of the force of gravity throughout the universe. This force makes every object in the universe attract every other object. He discovered that the strength of the force gravity between two objects is affected by the mass (amount of matter) and the distance between the objects. How does the sky change at various times during the year? Students: The sun changes elevation at midday throughout the seasons. There are also several prominent constellations visible during the winter and summer months. The three stars of summer appear in the constellations of Cygnus (The Swan), Lyra (The Lrye), and Aquila (The Eagle). In winter, Orion (The Hunter) dominants the night sky with Canis Major and Canis Minor following. Teachers: These changes are due to the rotation and revolution of the Earth. How does the length of day and night change during the seasons? Students: The length of day gets shorter from the summer to the winter. The length of the day gets longer from the winter to the summer. This is because of the tilt of the Earth and the position of the Earth at different points in its revolution around the Sun.
Teachers: The seasons result from two things the Earth s revolution around the Sun and the tilt of its axis. During the 365-day revolution, the Earth faces the Sun at different angles, so its surface receives direct sunlight on different areas of its surface at different times. During summer, the revolution around the Sun, the top half, or Northern Hemisphere, of the Earth leans toward the Sun. At this angle, the Northern Hemisphere gets the most direct sunlight, and the Southern Hemisphere gets the least. During winter, at the opposite side of the revolution, the Earth s axis tilts away from the Sun. The Northern Hemisphere gets the least direct sunlight, and the Southern Hemisphere gets the most. During fall and spring seasons, the Earth s axis is almost parallel to the Sun s. The Northern and Southern Hemispheres get nearly the same amount of sunlight. How does the shape of the moon change over a period of time? Students: The moon reflects the light of the Sun back into space, and some of the light reaches Earth. We see different phases because of the positions of the Earth and the Moon. One half of the Moon is always lighted by the Sun; most of the time only a part of the lighted half can be seen from Earth. Teachers: This is because of our viewing angle on Earth. When describing phases of the moon, the term wax means to increase in size and the term wane means to decrease in size. The moon waxes from new moon, waxing crescent, first quarter, waxing gibbous, full moon, waning gibbous, last quarter, waning crescent, and finally to new moon. What are stars, and how can they be described? Students: Stars are giant balls of burning gases that create their own light. Not all stars are the same. Some stars are hotter and larger than others. Teachers: Stars are giant balls of burning gases that emit light energy. Stars are enormous and have tremendous amounts of gravity. Stars range in size from being smaller than Earth to many thousands of times larger than our Sun. The size of a star doesn t exactly determine its temperature. Blue stars are generally the hottest, while red stars, which are the largest, tend to be the coolest stars. Our Sun is a medium sized star and produces heat in the middle range of temperatures. By most accounts, our Sun is a fairly boring star.
Why do some stars appear to be brighter than other stars? Students: Not all stars are the same size or distance from Earth. Our Sun is incredibly bright because it is so close to us on Earth. Some bright stars may be smaller but closer than other stars, while some very dim stars may be gigantic, yet very far away from us. Teachers: Absolute magnitude refers to how bright a star actually is. Apparent magnitude refers to how bright a star appears to be. Apparent magnitude depends on basically two things: the star s size and distance from Earth. From Earth, we see stars of different levels of brightness or magnitudes. A relatively small star close to Earth may seem brighter than a much larger star that is very far away. Because Venus is so close to Earth, it is often mistaken for a very bright star. Why do star patterns seem to not change shape? Students: Earth. Star patterns don t seem to change because the stars are so far away from each other and Teachers: Stars seem to stay locked in position relative to each other because they are so far away from the Earth. Just as distant trees seem to remain motionless, closer inspection would reveal blowing leaves, swaying branches, and perhaps even moving animals. Because stars appear to keep their patterns, people have been able to use these groupings or constellations to help guide them with navigation as well as to keep track of calendar time. In reality, all stars move, so the patterns will eventually change shape, though it will take thousands of years before it is noticeable here on Earth. How do shadows change throughout the day? Students: Shadows are longest as the Sun is rising and setting. They are the shortest at midday, when the Sun is most directly overhead. Teachers: As the Earth rotates on its axis, the Sun appears to move across the sky from east to west. The shadow of an object will move in the opposite direction from the incoming light. When the Sun is low on the horizon (sun up & sun down), the shadow will be the longest. Shadows will become smaller toward midday as light shines more directly on an object. What is the difference between a shadow stick and a sundial? Students: A shadow stick is a small pole that makes a shadow on the ground. It s a good way to show how the Sun moves across the sky by tracking how its shadow moves throughout the day. You can use a
shadow stick to help you tell time throughout the day. A sundial is also used to tell time by using shadows, but it s more accurate because of the way it s shaped. Teachers: Both a shadow stick and a sundial are used to tell time by creating and following the path a shadow makes on a flat surface. A shadow stick is a much simpler tool. As light hits the stick, a shadow moves across the ground. The places where the shadow falls can be marked to tell time. A sundial is a much more complex device that uses more advanced mathematical calculations in conjunction with latitude measurements to give both fairly accurate times of day and year. Essential Questions and Answers: What is the force that pulls objects toward the center of the earth, between the earth and the moon and the earth and other planets? Students: Gravity is the force that pulls matter towards Earth and keeps us from floating off into outer space! Gravity exists in all things. Bigger things have more of it than smaller things, but it s only noticeable in gigantic things like moons, planets, and stars. Gravity affects how heavy objects are. Things on the moon would feel lighter than here on Earth because the moon has less gravity than Earth. Also, it s the Sun s gravity that keeps the planets from drifting off into outer space! Teachers: Sir Isaac Newton, English scientist, 1642-1727, explored the effect of the force of gravity throughout the universe. This force makes every object in the universe attract every other object. He discovered that the strength of the force gravity between two objects is affected by the mass (amount of matter) and the distance between the objects. How does the sky change at various times during the year? Students: The sun changes elevation at midday throughout the seasons. There are also several prominent constellations visible during the winter and summer months. The three stars of summer appear in the constellations of Cygnus (The Swan), Lyra (The Lrye), and Aquila (The Eagle). In winter Orion (The Hunter) dominants the night sky with Canis Major and Canis Minor following. Teachers: These changes are due to the rotation and revolution of the Earth. How does the length of day and night change during the seasons? The seasons result from two things-the Earth s revolution around the Sun and the tilt of its axis. During the 365 day revolution, the Earth faces the Sun at different angles, so its surface receives direct sunlight on different areas of its surface at different times. During summer, the revolution around the Sun, the top half, or Northern Hemisphere, of the Earth leans toward the Sun. At this angle the Northern Hemisphere gets the most direct sunlight, and the Southern Hemisphere, gets the least. During winter,
at the opposite side of the revolution, the Earth s axis tilts away from the Sun. The Northern Hemisphere gets the least direct sunlight, and the Southern Hemisphere gets the most. During fall and spring seasons, the Earth s axis is almost parallel to the Sun s. The Northern and Southern Hemispheres get nearly the same amount of sunlight. How does the shape of the moon change over a period of time? The moon reflects the light of the Sun back into space, and some of the light reaches Earth. One half of the Moon is always lighted by the Sun; most of the time only a part of the lighted half can be seen from Earth. This is because of our viewing angle on Earth. When describing phases of the moon, the term wax means to increase in size and the term wane means to decrease in size. The moon waxes from new moon, waxing crescent, first quarter, waxing gibbous, full moon, waning gibbous, last quarter, waning crescent, new moon. What are stars, and how can they be described? Students: Stars are giant balls of burning gases that create their own light. Not all stars are the same. Some stars are hotter and larger than others. Teachers: Stars are giant balls of burning gases that emit light energy. Stars are enormous, and have tremendous amounts of gravity. Stars range in size from being smaller than Earth to many thousands of times larger than our Sun. The size of a star doesn t exactly determine its temperature. Blue stars are generally the hottest, while red stars, which are the largest, tend to be the coolest stars. Our Sun is a medium sized star, produces heat in the middle range of temperatures. By most accounts, our Sun is a fairly boring star. Why do some stars appear to be brighter than other stars? Students: Not all stars are the same size or distance from Earth. Our Sun is incredibly bright because it is so close to us on Earth. Some bright stars may be smaller but closer than other stars, while some very dim stars may be gigantic yet very far away from us. Teachers: Abosolute magnitude refers to how bright a star actually is. Apparent magnitude refers to how bright a star appears to be. Apparent magnitude depends on basically two things; its size and distance from Earth. From Earth, we see stars of different levels of brightness or magnitudes. A relatively small star close to Earth may seem brighter than a much larger star that is very far away. Because Venus is so close to Earth, it is often mistaken for a very bright star.
Why do star patterns seem to not change shape? Students: Earth. Star patterns don t seem to change because the stars are so far away from each other and Teachers: Stars seem to stay locked in position relative to each other because they are so far away from the Earth. Just as distant trees seem to remain motionless, closer inspection would reveal blowing leaves, swaying branches, and perhaps even moving animals. Because stars appear to keep their patterns, people have been able to use these groupings or constellations to help guide them with navigation as well as keep track of calendar time. In reality, all stars move, so the patterns will eventually change shape, thought it will take thousands of years before it is noticeable here on Earth. How do shadows change throughout the day? Students: Shadows are longest as the Sun is rising and setting. They are the shortest at midday, when the Sun is most directly overhead. Teachers: As the Earth rotates on its axis, the Sun appears to move across the sky from east to west. The shadow of an object will move in the opposite direction from the incoming light. When the Sun is low on the horizon (sun up & sun down) the shadow will be the longest. Shadows will become smaller toward midday as light shines more directly on an object. What is the difference between a shadow stick and a sundial? Students: A shadow stick is a small pole that makes a shadow on the ground. It s a good way to show how the Sun moves across the sky by tracking how its shadow moves throughout the day. You can use a shadow stick to help you tell time throughout the day. A sundial is also used to tell time by using shadows, only it s more accurate because of the way it s shaped. Teachers: Both a shadow stick and a sundial are used to tell time by creating and following the path a shadow makes on a flat surface. A shadow stick is a much simpler tool. As light hits the stick, a shadow moves across the ground. The places where the shadow falls can be marked to tell time. A sundial is a much more complex device that uses more advanced mathematical calculations in conjunction with latitude measurements to give both fairly accurate times of day and year.
Essential Vocabulary: gravity orbit universe sun moon stars planets seasons day night full moon Summer shadow shadow stick sundial constellation
Mastered Vocabulary Grade Level Vocabulary Enrichment Vocabulary sun moon stars planets seasons Summer Fall Winter Spring gravity day night orbit tilt rotate universe full moon new moon quarter moon crescent moon satellite reflection shadow sundial shadow stick constellation astronomy summer solstice winter solstice waxing crescent waxing gibbous waning gibbous waning crescent black hole comet