Wave Diffraction Lab

Wave diffraction is the spreading out of waves as they pass through a narrow gap or travel around the edge of an obstacle. It is a key wave property that occurs in all types of waves, including water, sound, and light waves.

Maximum diffraction occurs when the gap width ($d$) is approximately equal to or smaller than the wavelength ($\lambda$) of the wave ($\lambda \ge d$). In this case, the wavefronts emerge from the gap as almost complete circular waves.

When the gap width ($d$) is significantly larger than the wavelength ($\lambda$), the wave passes straight through the gap with minimal spreading. The waves remain mostly straight, with only slight curving near the edges.

No. During diffraction, the physical properties of the wave remain unchanged:

• Wavelength ($\lambda$): Remains constant.
• Frequency ($f$): Remains constant.
• Speed ($v$): Takes place in the same medium, so speed remains constant ($v = f\lambda$).

Only the shape and direction of the wavefronts change.

This comes down to the comparison between wavelength and obstacle size:

• Sound waves have relatively long wavelengths (from a few centimeters to meters), which match the sizes of doorways and corners, allowing significant diffraction.
• Light waves have extremely short wavelengths ($\approx 400 - 700 \text{ nm}$), which are far smaller than everyday objects, so light undergoes negligible diffraction under normal conditions.