The ActivityThe beauty of this activity is that it is entirely self contained in a single print out. Since students will be quantifying area by cutting out the shapes and finding mass on an electronic balance, you will want to print this out on the thickest piece of cardstock that you can find to ensure that the cutouts are large enough to measure. 
"Measure" the Time Since each dot represents the location of the object each day, counting the number of dots reveals the number of days that the object was in each zone. In this way, students will find that each shape represents 13 days of the planet's orbit Measure the "Area" Finding the swept area in this ellipse segments mathematically is quite challenging, so this activity uses mass as a way to compare one area to another. Since the paper/cardstock should be a uniform thickness, larger area corresponds to a larger mass. The exact mass of these segments will depend on the cardstock thickness but the segments should only vary a couple hundredths of a gram (the main challenge is convincing students that their result is about as close to the same as one can measure for something like this) Describe the Speed The dots around the orbit resemble a dot diagram or stroboscopic photograph from physics. If students aren't familiar with this approach to showing motion, I just tell them that the faster an object is moving, the farther it moves between "pictures". This should help students "discover" that the closer the object is to the star, the faster it is moving. Discussion QuestionsOnce students had an opportunity to "collect their data" regarding this object's orbit, I invited the class to discuss the following questions:
After discussing these, it's nice to jump to the PhET simulation to see what this changing velocity looks like in action and how Kepler's 2nd Law predicts this. Files
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