Abstract: An apparatus for demonstrating various phenomena associated with the earth's movement about the sun, having an upright fixedly attached to a base, at least one arm having two ends and being mounted on the upright in such a way as to be rotatable in a vertical plane, a crooked bearing housing for a spindle located near one of the ends, carrying a rotatable globe and constituting the axis of rotation thereof, all in such a way that, with respect to a line normal to the plane defined by the are, the axis of rotation of the globe is imparted a downward inclination of about 23.5.degree.. The apparatus further includes a light source unit attached to the arm at a point near the other end thereof and producing a light beam of a spatial extent sufficient to fully cover the globe, and drive means for causing the globe to rotate about its own axis, and for causing the arm to rotate in the vertical plane.