Sun's rotation period, Schemes and Mind Maps of Astronomy

Download Sun's rotation period and more Schemes and Mind Maps Astronomy in PDF only on Docsity! Sun’s rotation period Teacher’s Guide - Intermediate Level CESAR’s Science Case Sun’s rotation period CESAR’s Science Case 2 Introduction This is the teacher’s guide for “Sun’s rotation period” CESAR’s Science Case. Note that this guide does not contain full instructions to successfully develop the science case, those can be found at the student’s guide. This guide includes information about the learning purposes of the activity as well as about the material and background needed for it, so that the teacher may decide weather this laboratory is suitable for his class or not. This guide is also meant to help the teacher trough organising the activity, providing tips and keys for each step, as well as the solutions to the case’s calculations and the quiz. In this science case the students are to calculate the Sun’s rotation period using images from CESO (CESAR’s ESAC Solar Observatory). By the end of this laboratory, students will be able to: = Understand how fast the Sun moves. = Calculate velocities by tracking targets in time-separated images. = Explain what the rotation period is. = Make predictions and prove them with experiments. By completing this science case, students will find out how astronomical pictures can be used to obtain valuable data. Material What will they need? = The “Sun’s rotation period” Student’s Guide. = CESAR’s Booklet. = Computer with Web Browser and Internet Connection. = CESAR web tools. = Calculator (physical or online such as wolframalpha.com) and paper and pen. = Or a spreadsheet program such as Open Office, Google Docs, Excel or Numbers. There are no needed chapters from the booklet, however “Sun” is recommended to get more knowledge about the topics treated in this laboratory, and the introduction in “Earth Coordinates” may came in handy if students don’t have the basic knowledge about standard coordinate systems. Sun’s rotation period CESAR’s Science Case 5 Quiz The correct answers for the quiz are a d b d c b b d a c. The absurd answers for each question are c c d a b a c b d a. In case of doubt, the discussion of each question follows next: 1. The Sun rotates ¨ slower than Earth. ¨ faster than Earth. ¨ happier than Earth. ¨ once every 24h. It takes more than two weeks to the Sun to complete a rotation and only one day to the Earth to do so. 2. The rotation period is ¨ how fast the Sun rotates. ¨ the time that takes to a sunspot to move from one edge of the Sun to the other. ¨ how fast the Sun rotates about an alien spacecraft. ¨ the time that an object needs to complete one full rotation. No clarifications needed, answer d is the definition for rotation period. 3. If an object rotates very fast it ¨ must have a long rotation period. ¨ must have a short rotation period. ¨ must be very small. ¨ must be powered by a computer. Objects that rotate fast are usually small, buy they do not necessarily have to. If an object is rotating very fast, it takes very little time to complete a rotation, hence it has a short rotation period. Sun’s rotation period CESAR’s Science Case 6 4. We can calculate the rotation speed of the Sun by measuring the speed of sunspots because ¨ sunspots want to help us and they whisper the Sun’s differential rotation. ¨ sunspots are located in the Sun’s core, so we can measure their speeds with no disturbance. ¨ sunspots move through the surface. ¨ sunspots are located at the Sun’s surface, whose speed we want to measure. Sunspots don’t move through the surface, they move with the surface, whose speed we want to measure. 5. Once we know the speed of a sunspot, calculating Sun’s rotation period requires to know the ¨ distance between the initial and the final position of a sunspot moving through Sun’s surface. ¨ help of astronauts that are on ongoing missions at the Sun. ¨ number of degrees in a complete rotation. ¨ time that takes to the sunspot o go from the initial to the final position The distance between the initial and the final position of a sunspot moving through Sun’s surface, and the time that takes to the sunspot o go from the initial to the final position, are both needed to obtain the speed of the sunspot. But once we know the speed of a sunspot, calculating Sun’s rotation period requires only to know this speed and the number of degrees in a complete rotation. 6. Calculating the speed of a sunspot requires the ¨ cooperation of ESAC scientist, because their computers have to be used. ¨ distance between the initial and the final position of a sunspot moving through Sun’s surface. ¨ exact coordinates of a sunspot located in Sun’s surface. ¨ time that takes to a sunspot to move from one edge of the Sun to the other one. If we know the coordinates of a sunspot we’ll just know where the sunspot is, but nothing else. To obtain the speed of the sunspot we need both the distance between the initial and the final position of a sunspot moving through Sun’s surface, and the time that takes to the sunspot o go from the initial to the final position (not from edge to edge). 7. Earth’s rotation is the reason for day and night, Sun’s rotation is the reason for ¨ Sun’s day and night. ¨ the movement of Sun features. ¨ life in Earth’s core. ¨ Sun’s short rotation period. Sun’s rotation period CESAR’s Science Case 7 Day and night are produced by Earth’s rotation, because as the Earth is moving, the dark side and the side lighted by the Sun change over time. The Sun is always lighted because it is the light-source in the Solar System, so it does not have day and night. The Sun has a long rotation period, so only possible answer is b. 8. To calculate the speed of a sunspot you ¨ measured the distance between two sunspots. ¨ used a chronometer. ¨ looked at two different sunspots. ¨ tracked the sunspot in time-spaced images. To calculated the speed of a sunspot we only looked at one single sunspot, that was seen twice as explained in question five. 9. In science its common to ¨ have predictions before measuring. ¨ ignore the predictions only when you finished the measurement. ¨ use the results of an experiment to predict the value that you measured. ¨ ignore other scientist, because scientist know nothing. In science you should never ignore nor predictions nor scientist. It makes no sense to use the results of an experiment to predict the value that you measured, because if the values are already measured there’s no need for a prediction. In science its common to have predictions before measuring. 10. The Sun rotates ¨ so fast that it is flat. ¨ clockwise, like the Earth does. ¨ counter-clockwise, like the Earth does. ¨ faster in the poles. With the North orientated upwards, the Sun rotates counter-clockwise. Check the movement of the sunspots when you choose images of the same feature with a few days of difference, the sunspot moves to the right (counter clock-wise as seen from above).