Delta, Delta, Delta

In this experiment, learners construct an equilateral triangle using graph paper, a pencil, protractor and ruler. They also make a "laser triangle" using a laser pointer and front-silvered mirrors. Learners can use the geometric properties of an equilateral triangle combined with their understanding of the Law of Reflection to decide how to place the mirrors at each vertex so that the "laser triangle" fits their equilateral triangle. Learners also read about how Apollo astronauts helped scientists measure the distance to the Moon and the rate at which it's moving away from Earth by setting up special reflectors and lasers on the lunar surface.