List of Up down all around
1. Earth's Magnetic Field
2.Dipping Compass
3.Cyanometer
4.Skywatching
5.Moon Box
6.Twinkling Starlight
7.Steller Refraction
8.Sheet Erosion
9.Split a Stone
10. The Parallax Principle
11.Parallax Shift
12.Height Calculation
13.Rare Earth Metal
14. Magnetic Filtration
15.Box Periscope
16.Mapping the Ocean Floor