Why don't we notice diffraction in our daily life?

We don't notice diffraction in our daily life because it is most noticeable when light interacts with objects of similar size to its wavelength.

Diffraction is a phenomenon that occurs when a wave encounters an obstacle or a slit that is comparable in size to its wavelength. It is the bending of waves around the corners of an obstacle or aperture into the region of geometrical shadow of the obstacle. In our daily life, most objects we interact with are much larger than the wavelength of visible light, which ranges from about 400 to 700 nanometres. Therefore, the effects of diffraction are not easily observed.

The most common example of diffraction that we might encounter in our daily life is the spreading out of light as it passes through a small aperture, such as a pinhole. However, even this is not something we typically notice, because the effect is quite small and our eyes are not sensitive enough to detect it without the aid of special equipment.

Moreover, our brains are very good at interpreting the information received from our eyes in a way that makes sense to us. Even if diffraction effects were more noticeable, our brains would likely filter them out or interpret them as something else, because they don't fit with our usual understanding of how light behaves.

In addition, diffraction is more noticeable with waves of longer wavelengths, such as sound waves or water waves. For example, when sound waves encounter a barrier, they bend around it, which is why we can hear sounds from around a corner. Similarly, water waves spread out after passing through a gap in a barrier, such as a breakwater. However, these are not examples of light diffraction, and so they don't help us to notice the effects of light diffraction in our daily life.

In conclusion, while diffraction is a fundamental aspect of wave behaviour, its effects are not typically noticeable in our daily life due to the small size of the wavelength of visible light compared to the objects we interact with, the limitations of our visual perception, and the way our brains interpret visual information.