Light: Does it travel in a straight line?

We are often taught that light travels in a straight line. Well, in reality, light is an electromagnetic wave.

Visible light has a wavelength of about 400-700 nanometres, which is about 8 decimal places before a single digit. Just imagine how small it is. Wavelength is the straight line distance between two waves. It is due to this extremely small wavelength we are not able to see the light waves.

Also, light travels at a speed of about 3 x 10^8 m/s. If you would travel at this speed, you could go around the earth 7.5 times in one second. This is how fast it is. Due to this, light often seems like a ray travelling in a straight line.

The bending of light around an object's edge or through an opening when the size of the edge or opening is less than or about equal to the wavelength of light is called 'Diffraction'.