Mark Twain Simple Machines Science Workbook, Physics Middle Grade Books Covering Force, Motion, and Energy With Scientific Experiments, Classroom or ... Curriculum (Expanding Science Skills Series)

Mark Twain - Simple Machines, Grades 6 - 12 (Expanding Science Skills Series)

Electricity and Magnetism, Grades 6 - 12: Static Electricity, Current Electricity, and Magnets (Expanding Science Skills Series)

Mark Twain - Astronomy, Grades 6 - 12 (Expanding Science Skills Series)