Our solar system is made up of the sun, 8 planets and their moons.
The earth rotates (spins) once every 24 hours. If you stand in one place and turn all the way around, you have rotated. The action of the earth turning or spinning around its center. Earth moves in a circle around the sun once every 365.25 days. While accurate, it is hard to study something so tiny and far apart.Īn orbit is the path an object follows as it moves around another one. Also, if you modeled the distance to scale, the baseball would be about 100 feet away from the tiny grain of rice. For example, if the sun was modeled to be the size of a baseball, Earth would need to be smaller than a grain of rice (2 mm)! You would barely be able to see it. Why is it sometimes not practical to use to scale models when representing objects in space? ANSWERĭue to the vast scale of objects in space, it is not always practical to use scale models. This way, anywhere you are on earth, the sun will be as high in the sky as it can be at noon. To adjust our clocks so that everyone has daytime during the same hours, it is necessary to use time zones. However, this doesn’t happen at the same time in every location on Earth. How are our 24 time zones related to Earth’s rotation? ANSWERĮach day the sun appears to rise, move across the sky and set. The view of planets from earth changes all the time. Sometimes planets are on the same side of the sun and sometimes on opposite sides. Why can we only see certain planets at certain times? ANSWERĮarth and all the other planets in our solar system are both rotating and orbiting the sun. A concept called stellar parallax provided evidence that we orbit the sun. Since the sun appears to move across the sky, it is easy to understand why humans believed this for a long time. What is a geocentric view of the universe? What evidence showed us it is not correct? ANSWERĪ geocentric view of the universe is the idea that everything orbits around the Earth. However, as time goes by the path of the pendulum changes, providing evidence that the surface it is sitting on (the earth) is rotating. The swinging pendulum would always trace a straight line as it swings back and forth if it were sitting on an unmoving surface. What evidence do we have that the Earth rotates? ANSWERĪn invention called a Foucault pendulum provides evidence that the Earth is rotating on its axis. (4 years x 0.25 day = 1 day added every 4 years.) Since it takes Earth 365.25 days to orbit the sun, but our normal calendar is 365 days, we add an extra day to our calendar every four years. Why do we have a leap year in our calendar every four years? ANSWER These two motions are happening at the same time. It rotates once every twenty four hours, while also orbiting the sun once every 365.25 days. How many times does Earth rotate on its axis in one year? ANSWERĮarth rotates (spins) 365.25 times in a year. During that time, all locations on Earth experience day and night because they will be facing toward the sun for part of the day and away from the sun for another part (night). What happens when Earth rotates on its axis and how long does it take? ANSWERĮarth rotates once on its axis once every 24 hours. If the sun is directly overhead, the shadow will be very short. If the sun is close to the horizon, a shadow will be long. The length of a shadow is determined by where the sun appears to be in the sky.
After Video The shadow of a groundhog (or anything else) is determined by what? ANSWER.Certain stars are visible from Earth at certain times each year. Why do the stars visible in the night sky change throughout the year? ANSWERĪs the Earth orbits the sun, the night side of the earth faces a different part of the galaxy. It also spins on its axis once per day, which takes 24 hours. In one year, the Earth orbits the sun one time. What can you say about Earth’s motion in one year? ANSWER Earth rotates on its axis once every 24 hours, so the part of the Earth that is in the light (day) rotates into the darkness (night). Sunlight shines on one side of Earth, but the other side faces away from the sun and is dark. How does the motion of the Earth cause day and night? ANSWER After it passes overhead, the shadows begin to grow again in the opposite direction. As it gets higher in the sky, the shadows get smaller. Long shadows point away from the sun as it rises in the east. Before Video What happens to shadows throughout the day? Why? ANSWERīecause the Earth rotates on its axis, the sun appears to move across the sky.