Name Class Date

Astronomy Ellipse Lab

Eccentricity is a measure of how “out of round” and ellipse is. The formula to calculate eccentricity (e) is e = d where d is the distance between foci

L and L is the length of the major axis.

1.  Draw 3 ellipses. Calculate the eccentricity of each ellipse and compare each based on their eccentricity.

a.  On the attached worksheet, place pins in the locations marked “1”. These will be the foci of the first ellipse.

b.  Using the string provided, draw your ellipse, label it ellipse 1, and calculate the eccentricity of ellipse 1. Record your work in the table below.

c.  Move the pins to locations “2” and draw your second ellipse, label it ellipse 2. Calculate the eccentricity of ellipse 2. Record your work in the table below.

d.  Move the pins to locations “3” and draw your third ellipse, label it ellipse 3. Calculate the eccentricity of ellipse 3. Record your work in the table below.

Ellipse 1 / Calculations SHOW YOUR WORK
d =
L =
e =
Ellipse 2 / Calculations SHOW YOUR WORK
d =
L =
e =
Ellipse 3 / Calculations SHOW YOUR WORK
d =
L =
e =
Planet / Eccentricity
Mercury / 0.206
Venus / 0.007
Earth / 0.017
Mars / 0.093
Jupiter / 0.048
Saturn / 0.056
Uranus / 0.047
Neptune / 0.009

2.  Of the three ellipses you drew, which is the most eccentric?

3.  Of the three ellipses you drew, which is the least eccentric?

4.  Of the three ellipses you drew, which is most like the Earth? Explain your answer.

5.  Draw a diagram of the Solar System in the space below. Be sure to include the Sun and place the Sun and the planets in their correct positions. Label your diagram and include approximate orbital paths.