3D Eclipse Gizmo Answer Key

Name: Royce Guerra Date: 02-02-2022 Student Exploration: 3D Eclipse Directions: Follow the instructions to go through the simulation. Respond to the questions and prompts in the orange boxes. Vocabulary: eclipse, lunar eclipse, path of totality, penumbra, solar eclipse, umbra Prior Knowledge Questions (Do these BEFORE using the Gizmo.) 1. Have you ever seen an eclipse? If so, describe what you saw. No, I have never witnessed an eclipse, though I would like to. 2. How often do you think eclipses happen? Most likely annually? Since eclipses are uncommon, I assume they occur annually. Gizmo Warm-up If you see a two-dimensional image of the Earth, Moon, and Sun, you might predict that an eclipse occurs every time the Moon passes in front of or behind Earth, or about twice a month. However, eclipses occur much more rarely. The 3D Eclipse Gizmo shows two views of the Earth, Moon, and Sun: a top view (above) and a side view (below). The sizes of the Earth, Moon, and Sun are not to scale. (If they were, the Earth and Moon would be microscopic!) 1. Set the Simulation speed slider to a middle value, and click Play ( ). Based on the top view on the SIMULATION pane, describe the motions of the Sun, Earth, and Moon. The moon is going around the earth and the earth is going around the sun 2. Click Reset ( ), and then click Play again. This time, focus on the side view at the bottom of the SIMULATION pane. What do you notice about the Moon’s orbit? When viewed from the side, it appears as though the earth and sun are going to collide as it round the planet, however it is simply the earth passing in front of the sun at certain moments. Activity A: Solar eclipse Get the Gizmo ready: ● Click Reset. ● Under Shadows, select Moon. ● Set the Moon angle to 0.0°. Introduction: There are two parts to the Moon’s shadow. The umbra is the central, darkest portion of the shadow. An observer standing in the umbra cannot see the Sun. The penumbra surrounds the umbra. An observer in the penumbra sees part of the Sun. Only the umbra is shown in the 3D Eclipse Gizmo. Question: What controls whether a solar eclipse will occur? 1. Observe: Click Play and then Pause ( ) when the Moon is directly between the Earth and Sun. (If you go too far, you can click the Back button to step back.) A. What do you notice about the Moon’s shadow? The shadow of the moon extends all the way to the earth. B. Under Views, select Earth. What do you see? The moon's shadow and the earth are all I can see. Any person standing in the Moon’s shadow will experience a solar eclipse. During a total solar eclipse, the entire disk of the Sun is blocked by the Moon. 2. Observe: Set the Simulation speed to a lower setting and click the Back button until just before the Moon’s shadow crosses Earth’s surface. Click Play and observe. A. What do you notice? The shadow passes by Earth, but it returns after about a week. B. The path the Moon’s umbra traces across Earth’s Most likely it's just dark. surface is called the path of totality. What would you see if you were standing in the path of totality? 3. Record: Click Reset. Set the speed to a higher setting and click Play. Use the Gizmo to determine the dates of the first six solar eclipses of the year. Record these dates below. January 11, February 10, March 11, April 9th, May 9th, June 8th Do you think solar eclipses really happen this often? Explain. No, as I don't believe the moon could ever completely block the sun or that its shadow could ever be too high or low. 4. Explore: Click Reset. A solar eclipse does not occur every month because the Moon’s orbit is tilted 5.14° relative to Earth’s orbit. To model this, set the Moon angle to 5.1°. Play the simulation until January 9. Click Pause, reduce the speed, and click Play. What do you notice about the path of totality now? Instead of the center of the globe, the path of totality is more inclined to the button region. 5. Explore: Advance the simulation to February 8, and again play the simulation at a low speed. Does the umbra cross Earth’s surface this time? From my vantage point, it doesn't appear to traverse the surface of the earth. The umbra appears to be passing beneath the earth's surface without making contact with it. In this situation, a total solar eclipse will not be visible from any location on Earth’s surface. 6. Record: Use the Gizmo to find the dates of the next three solar eclipses. Be sure to check carefully whether the Moon’s umbra crosses Earth’s surface. Record these dates below. June 8th, July 7th, Dec 2th Do you think this frequency of solar eclipses is more realistic? Explain. Yes, because it makes sense that solar eclipses, which typically occur three times a year rather than monthly, are rare. 7. On your own: Experiment with different Moon angle values. How does the angle of the Moon’s orbit affect the number of solar eclipses that occur in a year? Solar eclipses happen about once a month when the angle is low, but when it is high, it either doesn't happen at all or only happens three to four times. 8. On your own: Return the Moon angle to 5.1°, and increase the Moon distance to 1.50. How does increasing the Earth-Moon distance affect the occurrence of total solar eclipses? The moon's angles operate similarly, therefore there are fewer solar eclipses the farther away we are from the sun. Activity B: Lunar eclipse Get the Gizmo ready: ● Click Reset. Under Shadows, select Earth. ● Set the Moon distance to 1.00 and the Moon angle to 0.0°. Introduction: A lunar eclipse occurs when the Moon goes into Earth’s shadow. If the Moon goes into Earth’s penumbra, it is called a penumbral lunar eclipse. If the Moon goes into Earth’s umbra, it is a total lunar eclipse. A partial lunar eclipse occurs when only part of the Moon goes into Earth’s umbra. (Note: Earth’s penumbra is not shown in the Gizmo.) Question: What controls whether a lunar eclipse will occur? 1. Observe: Set the Moon angle to 0.0°. Click Play, and then click Pause when the Moon is in Earth’s shadow. Select the Moon view. What do you see? I see the moon but I don't see the earth's shadow automatically, I only see it later 2. Observe: Set the speed to a lower setting and click the Back button until just before Earth’s shadow crosses the Moon. Click Play and describe what you see. Although I can see the moon, I cannot see the earth's shadow. 3. Infer: Select the Earth view. Who on Earth would be able to see the lunar eclipse? Explain your answer. The folks who are in the moon's line of totality will be able to observe the lunar eclipse. 4. Record: Click Reset and select the Moon view. Set the speed to a higher setting and click Play. Use the Gizmo to determine the dates of the first six lunar eclipses, and record below. January 24, February 24, March 25, April 24, May 23, June 22 Do you think lunar eclipses really happen this often? Explain. I'm not sure if they occur this frequently, but based on how the Gizmo appears, it may do so. 5. Explore: Click Reset. Set the Moon angle to 5.1°. Play the simulation until January 24. Click Pause, set the speed to a low value, and click Play. A. Is there a lunar eclipse this time? No B. Why not? (Hint: Look at the side view on the bottom of the SIMULATION pane.) From the side view the moon isn't in the earth's shadow but from the moon view it is under the earth's shadow 6. Record: Use the Gizmo to find the dates of the lunar eclipses in one year. Be sure the Moon is actually darkened by Earth’s shadow for each eclipse. Label each eclipse a total eclipse (moon is completely darkened) or a partial eclipse (only part of the moon is darkened). June 22, July 21-partial lunar eclipse, December 16 Do you think this frequency of lunar eclipses is more realistic? Explain. Yes, because a lunar eclipse cannot occur every month due to the moon being at different angles, hence this frequency is more reasonable. 7. Think and discuss: A person living in North America can see 15 lunar eclipses in the 2010–2020 decade. In the same time period, only two solar eclipses can be observed in North America. Why will more lunar eclipses than solar eclipses be visible from North America in this decade? If possible, discuss your answer with your classmates and teacher. I'm not totally sure why people in North America can watch 15 lunar eclipses but only 2 solar eclipses because I was unable to discuss this with a classmate or a teacher.