When the aperture is larger than the wavelength most waves pass through and little diffraction occurs and when the aperture is much smaller than the wavelength most waves are blocked. Do you need to teach the transmission, absorption, reflection, and refraction of waves in your 6th, 7th, or 8th grade science classroom This complete unit will also help you cover Utah SEED 8.2.5. The size of the aperture (or object) determines the extent of diffraction, with the most significant diffraction occurring when the aperture is of the same order of magnitude as the wavelength of the wave. Diffractionĭiffraction is the spreading out of a wave when it passes through an aperture (gap/hole) or around an object. IMPORTANT NOTE: If a wave enters a medium at 90º to the surface (parallel to the normal) it is not refracted. Diffraction involves the bending or spreading out of a sound wave in a single medium, in which the speed of sound is constant. The angle of refraction is greater than the angle of incidence.The angle of refraction is less than the angle of incidence.In air there is little resistance (acoustic impedance) to the sound. The media will absorb, reflect or impede the sound energy flow in accordance with the acoustic properties of the media and the wavelength of the sound wave.
The angle of refraction is larger or smaller than the angle of incidence depending on how the speed changes: Sound Waves transfer sound energy by vibrating the particles of the various media the sound waves pass through. Refraction occurs because waves travel at different speeds in different mediums and this change in speed is caused by differences in density between the mediums.