<em>So let me try to repeat that: San Francisco sourdough tastes sour because of a unique local bacteria called lactobacillus San Francisco. That, and a yeast called candida milleri are the real secret to San Francisco sourdough bread. In other words, the secret ingredient is no secret at all: It's blowing in the wind.</em>
Refraction is the change in direction of waves that occurs when waves travel from one medium to another. Refraction is always accompanied by a wavelength and speed change. Diffraction is the bending of waves around obstacles and openings.
