  We demonstrate that a de Broglie wave of a particle in a gravitational field
turns towards the region of a smaller gravitational potential, causing the
particle to fall. This turning is caused by clocks running slower in the
smaller potential. We use the analogy of ocean waves that are slower in
shallower water and turn towards beaches. This approach explains the free fall
qualitatively and quantitatively without postulating motion along geodesics and
with only elementary algebra.
