PURPOSE: To illustrate aspects of vector algebra.
DESCRIPTION: To provide quantitative examples, project a grid on the blackboard and read off coordinates. Demonstrate coordinate invariance by translating and rotating the grid while A+B=C is preserved by leaving the arrows fi xed on the board.
SUGGESTIONS: This demonstration is for the lecture halls where magnetic vectors stick to the magnetic blackboards.
REFERENCES: (PIRA unavailable.)
EQUIPMENT: Overhead projector with transparencies, magnetic vectors.
SETUP TIME: None.