The sunset project A database project on the observation of sunsets Caution

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1 A database project on the observation of sunsets Caution Never direct look into the sun. Always use protection glasses. Ask the teacher in case of doubt. Background information A sunset does not happen at every location at the same time. It does not even happen at the same time at one location within a year. The path of the earth around the sun during a years time and the inclination of the earth's rotation axis against its plane of motion (ecliptic) result in different times for sunsets at the same location. Page 1 of 7

2 Figure 1: During a day, the sun comes up in the east, reaches south at noon and goes down in the evening in the west. The core of the project is to simply observe a sunset and write down the time, location and direction of the observation. These data are input into a database. A higher scientific level can be entered by analysing the recorded data in the database. Another part of the project might be simply presenting photos of the sunset, which gives very young pupils a nice low level entry to science observations. Figure 2: Taking a photo of a sunset is a motivating task to join this science project. Objectives Pupils will in this project learn about the rotation of the earth around her axis of rotation the movement of the earth in the ecliptic (plane of motion around the sun) the definition of time units the meaning of time zones the geographical coordinate system how to manage outside observations how to use a database Page 2 of 7

3 using a camera to take a picture how to publish a report/photos on the Internet Age group The project contains different components, so it is applicable to pupils of primary schools as well as to pupils of secondary schools, depending on the part of the project the pupils are joining. Table 1 shows a summary of activities pupils can participate and the corresponding age range. Age [Years] Task Type of task Description Observation Report on observation Learning about time units Taking photos Database input Learning about geographical coordinates Learning about time zones Publish photos Database research Outdoor activity Home work or computer room activity in group work Curricular teaching of physics Outdoor activity Computer room activity (1 computer, beamer) Curricular teaching of mathematics Curricular teaching in geography Computer room activity in group work Computer room activity in group work Table 1: Age groups and activities in the sunset project. The pupils take notes on location, date, time and direction of sunset. The pupils prepare a report of the excursion, including the written notes. This report might be published on the web or just go into the private notes of the pupil. The pupils learn about the physics of units of time measurement (Year, Month, Day, Hour, Minute, Second). The pupils take photos of the sunset. The pupils input their observation into the Xplora web database. The pupils learn how each location on earth is addressed. The pupils learn the reason for creating time zones, and the name conventions for existing ones. The pupils create a publication on the schools homepage or on a page supplied by Xplora. Xplora might run annual photo contests. The pupils learn how to research data from a database and how to interpret the data. Page 3 of 7

4 Cooperation According to table 1 there are several scenarios of cooperation possible, ranging from no cooperation (isolated observation) to clusters of classes specialising in a subtask. Isolated action In this case a class would go out into nature and take the observation (see student guide). Depending on the pupils age, after observation would follow the preparation of the report (mandatory in all cases), a publication of the report or a photogallery (optional) on a web server, a teaching unit on the derivation of time units from astronomy (recommended) and modern time standards (optional). The other activities in table 1 are optional and support the project. For the teaching units on time zones and geographical coordinates, a study of the database content would be helpful. In addition an astronomy program like xephem [1] can help understand the effects on sunset, location and time zones. Table 2 shows the nights at 4 different locations at the time of the northern winter solstice. The first two locations have a comparable longitude, the latter two and the first have a comparable latitude. What can be seen: Places at the same latitude have the same length of night (day) but it starts at different times in the UTC (Universal Time Coordinated), the official world time used in flight and military operations. It is the successor to the former Greenwich mean time (GMT). Places at the same longitude have a different length of night (day). The center of the night period however is at the same UTC. This version of cooperation can lead to the deepest subject information about time and coordinates on earth. Page 4 of 7

5 The night at a glance in some cities Location Berlin Latitude: ' (North) Longitude: ' (East) Night is from about 17h UTC to 5h UTC. Windhoek Latitude: ' (South) Longitude: ' (East) Night is from about 19h UTC to 3h UTC. Page 5 of 7

6 The night at a glance in some cities Location Irkutsk Latitude: ' (North) Longitude: ' (East) Night is from about 11 UTC to 23h UTC. St. Johns Latitude: ' (North) Longitude: ' (West) Night is from about 21h UTC to 10h UTC. Table 2: The night at northern winter solstice at 4 different locations. Page 6 of 7

7 Cooperation with other schools In case some project partners choose a cooperation between classes, the broadband of the topics might be larger. The groups should have different focus of topics with an overlap in date, time and location measurement. The cooperation must not be over long distances, even local clusters might be helpful, when for example a class of computer science in a secondary school might help a class in a primary school to get their photos into a website. The standard medium for information exchange will be , but for local clusters all kind of communication will be possible. Links [1] [2] Page 7 of 7