The Oldest Lunar Rocks
Grade Level: 5-8
Body: Earth's Moon
Short Description: A list of the ages of the oldest lunar rock samples is grouped into families with about the same average ages to estimate the age of the lunar mare.
Grade Level: 5-8, 9-12
Body: Sun, Mercury, Venus, Saturn, Kuiper Belt & Oort Cloud, Earth's Moon
Short Description: The introduction clearly explains the apparent "collisions," eclipses, transits, and occultations. The collection includes problems on synodic periods, planetary conjunctions, geometry, fractions, linear equations, and probability. The Table of Contents clearly separates middle school level problems from high school problems.