These hands-on activities are a great way for students to gain perspective on the relative sizes and distances of each planet, the relationship between the sun and Earth, and much more.

This illustration from the Lunar and Planetary Laboratory shows the approximate sizes of the planets relative to each other. Note that the planets are not shown at appropriate distances from the Sun.

This site from Cornell University provides a discussion of how Aristarchus arrived at his conclusions of the distance from the Earth to the Sun and Moon. Also has his methods for determining the size of the Moon and the Sun.