## Wednesday, November 9, 2016

### Planital Orbit

Yesterday my students finished up the assignment on ellipses where they created and graphed the equations for each of the planets in the solar system.

I realize that I did not include gravitational pull and other factors but I created a simplified version so students could see the use of ellipses in real life.

I had them begin with the information on The Universe Today for both the closest and farthest distances from the sun.  The farthest distance was designated as the a value while the closest distance was designated as the b value for the basic equation.

 Equations

After creating the basic equation, they calculated the value of c using c^2 = a^2 - b^2 because they needed it to figure out eccentricity or e = c/a.  After getting this done for each planet, they used Desmos to graph the orbits.

 Graphs
The hardest thing was getting students to recognize that what Desmos produced was not necessarily correct because the window had to be adjusted so the major axis appeared correctly.  It was a learning experience and this activity gave students a better understanding on how the resultant value of eccentricity.