Here's why:
* Diffraction is the bending of waves as they pass around an obstacle or through an opening. The amount of diffraction depends on the relative size of the wavelength compared to the size of the obstacle or opening.
* Wavelength is the distance between two consecutive crests or troughs of a wave.
* Shorter wavelengths diffract less, meaning they tend to travel in straighter lines.
* Longer wavelengths diffract more, meaning they bend more around obstacles and spread out more.
Think of it this way: imagine a wave traveling through a narrow opening. If the wavelength is much smaller than the opening, the wave will pass through with little bending. But if the wavelength is similar to or larger than the opening, the wave will bend significantly as it passes through.
Example:
* Light waves have very short wavelengths. This is why light from a flashlight can be focused into a narrow beam, and why we can see sharp images through a pinhole camera.
* Sound waves have much longer wavelengths than light waves. This is why sound waves can easily bend around corners and why we can hear someone speaking even if they are hidden behind a wall.
