This demonstration assumes that the students already have learned about orbits and lunar phases. Before
beginning the demonstration, I explain the term "line of nodes," then enlist one student to hold the hula
hoop horizontally over the light bulb Sun (if using), ensuring that the Sun is in the center of the hoop, and
in the same plane. I orient the Moon’s orbit hoop with an exaggerated inclination with respect to the
Earth’s orbit plane but reiterate to the students that the angle is not actually that large! With my
explanation of the line of nodes still fresh in the students’ minds, I show them where the line of nodes
would be by placing my fingers at the intersection of the orbits and then ask them to visualize a line