Interference and diffraction of waves

By using a water interactive device, understand the interference and diffraction of waves. The exhibit consists of three circular transparent water trays, a spotlight, and a water dispenser. Viewers can watch the water device hitting the water surface in different ways, and the water patterns are then projected onto the ground by a spotlight to present three different wave patterns: single click waves, double click interference waves, and diffraction waves. Target audience: Adolescents aged 6-15. Display format: Electromechanical interactive device operation instructions (audience experience) 1 Click the button and select the water mode; 2. Observe the changes in waves and understand their interference and diffraction. Description of the intrinsic connections between storylines and exhibits in wave optics, interference and diffraction of waves.

Interaction type: Interactive installation. The unit is designed for unsupervised public use: controls are recessed or shielded, moving parts are enclosed, and the interface is operable by a child of about six with no instruction. Where a screen is used, the language can be switched without changing the hardware, and the content can be replaced on site.

When light encounters obstacles or small holes during its propagation, it deviates from its straight path and travels behind the obstacles, which is called diffraction of light. The diffraction of light, like the interference of light, proves that light has wave like properties. The phenomenon in geometric optics where diffracted light waves deviate more or less from the law of linear propagation when encountering obstacles. Geometric optics states that light propagates in a uniform medium according to the law of straight lines, and at the interface between two media, light propagates according to the laws of reflection and refraction. However, light is an electromagnetic wave, and when a beam of light passes through a perforated barrier, its intensity can spread to the geometric shadow area defined by the law of linear propagation, causing certain dark spots or lines to appear in the geometric illumination area. In summary, the diffraction effect causes the light intensity distribution in the space behind obstacles to differ from both the light intensity distribution given by geometric optics and the light intensity distribution during free propagation of light waves.