REFRACTION IS THE BENDING OF A WAVE AS IT PASSES AT AN ANGLE FROM ONE MEDIUM TO ANOTHER. WHEN A WAVE MOVES FROM ONE MEDIUM TO ANOTHER, THE WAVE'S SPEED CHANGES. WHEN A WAVE ENTERS A NEW MEDIUM AT AN ANGLE, THE PART OF THE WAVE THAT ENTERS FIRST BEGINS TRAVELING AT A DIFFERENT SPEED FROM THE REST OF THE WAVE.
