Figure 1: A series of light and dark bands are shown along the edges of the razor blade’s shadow.

Materials:

• Laser
• Razor Blade
• Stand to Hold Razor Blade
• 75 mm Lens
• Lens Holder
• Screen

Demo:

Light from a laser shines onto the sharp edge of a razor blade. A screen, located behind the razor blade, shows its shadow. Near the edges of the shadow, a series of light and dark bands can be seen, as shown in the picture above.

Explanation:

The series of light and dark bands are created from the edge diffraction phenomenon, which occurs when a monochromatic light hits an object. In this demo, the laser emits a beam of red light that hits the edge of the razor blade. The bands are then produced on the screen behind the blade, which appears as thin bands of light outlining the shape of the object that become dimmer the further away from the blade they are. In Figure 2, the intensity of the diffraction pattern as a function of the distance Y from the edge of an object is shown. It appears to have highest intensity in magnitude the closer it is to the object, but considerably decreases the further away from the object the position is.

Figure 2: Intensity as a Function of Position Y from the Object