Activity 8: Scaling Our Solar SystemMay 8, 2008 through May 15, 2008 |
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In this activity we will:
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| In this investigation your team will propose a method to model our Solar System in the classroom or on the school ground. To help learning how to scale we will determine the scale of image of your handheld above. Measure the width of your real screen and of the scaled screen in the image. What number would you use to reduce the width of the real screen to the scaled screen? This will be your scale factor. That is, you will divide the real measure by the factor. In the example at the right we have the real size as 4.5 cm and the scale size is 1.6 cm. The scale factor is 2.8125. This means that you could divide the real measure by 2.8125 and you would get the scaled size. Test your scale factor with a measure of another part of the handheld. If you think you have it, then report the factor to the class when the teacher calls for it. All students should have discovered the same value for the factor. The scale would be: 1 cm = 2.8125 cm |
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Visit a resource to get the data for the Diameter of each planet and the distance it is from the Sun. Place this data in your lab notebook and site your reference. Recall that Pluto is no longer considered a planet. Since the Sun is so much larger that any of the planets, we will not put it in our model Solar System, except as a point of reference. |
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Place this data in your handheld. Press  to access the List Editor and
then move the cursor to the header of the 1st column. Press  until you
get tired. |
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| Now name the lists to hold the names of the planets (LNAME), the
diameter of the planet (LDIA) and the average distance from the Sun
(LDIST). To do this press  [TEXT] to access the Text Editor. Recall that you will
highlight the word Done when finished with a name and then  . Also if
you make a mistake just press to delete one letter at a time. Move
to the next column for the next list and name it in the same way. |
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| Enter your data for the planets. For the names you will need to make
the lists categorical. To do this, put the first name in quotes. Then
the other names will not need the quotes, but will be understood as
words. Move your cursor into the body of the lists and then enter the Text Editor as before. |
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Recall that names may be no more than 6 letters. Make sure that you use the same units of length for all the diameters and the same unit of length for all of the orbit distances. The units used for diameter and distance need not be the same. |
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Now that you have the data, we want to determine a factor to use in making the distances small enough to make the Solar System model in the classroom or on the school grounds. Check with your teacher about where you will build your model. Determine the greatest distance you have available for you to put the planet in its scaled orbit. Also you will need to think of the largest sphere you could obtain/use to model the planet. Your scale can be in two parts, one for the planet and a different one for the orbit. This may be a factor in the selection of which team’s scale factor(s) will be used. For example you could have a scale of 1 cm = 1 000 000 km for the orbit and 1 m = 40 000 km for the diameter. |
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Depending on which measure you want to experiment with first, you will need to insert a list to hold the scaled values. Place your cursor in the header of the list you want to experiment with and press [INS] to add
a new list. Name it with an S on the end so we can know it is the
scaled value. So we would have (LDIAS) and (LDISTS). |
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In the header of the list divide the real list by some factor to create a list of measures to use in the scale model. Access the list name by pressing [STAT]. |
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In the example to the right, using the factor of 7777 we would need spheres ranging from 2 cm to 58 cm to model the planets. Note: Notice the values used for the diameters may not be correct. Repeat the process for the diameters until you are satisfied. |
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Continue the determination of a scale for the orbit distances. |
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| Using the list make a plot showing the relationships for the planet and
the diameter or distance. You will only be able to have 7 names for
planets, so you may delete Earth, or one of the Outer Planets. Make
sure you keep a record of the data so you may replace it as needed. To delete an item in a list, just place your cursor on the item to delete. Make sure you delete the corresponding values in the other lists. |
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Press [PLOT] to access the Plot Editor. Set up a plot as you feel appropriate. Report the plot to your teacher. |
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| When you have determined your scale factors report them to the class.
This can be done through a Quick Poll or in the Form on the Activity
Center, or using a WhiteBoard. |
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Look at the factor used by other teams and see how close you are to their picks. Vote on the scale team that has the scale you want to use to build your model Solar System and then when the results are in, as a class – build it! |
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