In this picture, the stem of the flower appears to be out of place. This is caused by the refraction of light rays. The light rays which produce an abnormal image are the ones that travel from the underwater portion of the stem through the water, across the boundary, in the air, and to the human eye. The light rays refract at the boundary. The human eye will see this distorted image because the brain sees the location of the image as the same location where the refracted or reflected rays intersect. So to the brain, the location of the image is where the refracted or reflected rays intersect with each other. The brain and the eye assume that light rays travel in a straight line and extend backwards until they get to the point where they intersect. However, the light rays from the part of the stem under water intersect in a different location than the location where the light rays from the part of the stem above the water do. This is what causes the human eye to see the image as it is.
