Materials Keppler's First Law: two tacks, a loop of string, a protractor, a piece of cardboard and a piece of blank white paper 1. Exercises Kepler's First Law: The planetary orbits are ellipses, with the Sun located at one focus. For this part of the lab, you will work with your lab partners. Your instructor will give each of you two tacks, a loop of string, a piece of cardboard, and a piece of blank white paper. Use this material to draw an ellipse on one of the pieces of cardboard. How did you do so