run something into something. 1. to guide or route something, such as a wire or a pipe, into something or a place. The worker ran the circuit into each room. He ran in the circuit as specified. 2. to guide something into something; to drive or steer something into something else.
A change of color to a blue-black or purple color suggests that starch is present. If there is no change in color, this suggests no starch is detectable. Note the change of the iodine to black on the potato (right) but not the apple (left). (10% Tincture of iodine.) Potato contains starch, but apple does not.
That changes the way electrons are confined, and that in turn, changes spacing of the energy levels. The iodine/starch complex has energy level spacings that are just right for absorbing visible light- giving the complex its intense blue color. This Iodine Test for Starch is used to determine the presence of starch in biological materials.