Exp 01 - From Shadows to Diffraction | Optics

This video is the first in a series of experimental physics lectures. The instructor introduces a course designed to teach physics through simple, self-designed experiments, targeting a mixed audience of students and teachers. The first module focuses on optics, starting with the fundamental concept that light travels in straight lines. Through a series of demonstrations, the instructor shows how shadows are formed and how their sharpness depends on the distance between the object and the screen, as well as the size of the light source. He then introduces the idea that light can bend, leading to the concept of diffraction. Using a laser and a thin wire, he demonstrates that when an obstacle’s size is comparable to the wavelength of light, the ray optics approximation fails, and diffraction patterns emerge. The video explains the conditions under which ray optics is valid (when obstacle sizes are much larger than the wavelength) and introduces the wave nature of light. The experiments are clearly presented, and the instructor encourages viewers to explain the observed phenomena, fostering a deeper understanding of physics principles.