Eureka! Eureka! I see the Sine!
Milind Sawant, PhD
R&D / AI, Sr. Executive 20+ years at Siemens Healthcare | Led up to 50 People with $15M+ Budgets | Developed from Concept to Launch Products Used Globally by 200M People | Expertise in AI/ML and DFSS for Medical Systems
You don't need a science laboratory or a peer reviewed journal to enjoy Physics! Sometimes a bathroom is more than enough. By the way, any similarities to Archimedes is purely coincidental and limited to the location. I didn't run out :)
When I entered the bathroom to brush my teeth, I noticed some streaks of sunlight entering from the skylight window on top and reflecting off the vanity mirror (see photo on the left). At first, I dismissed it as rays of sunlight visible due to dust particles. Then I realized that the streaks of light were equidistant and almost like a 3D hologram. There was nothing in the skylight or the mirror to create such a unique pattern. I put a black poster board to observe it clearly and saw the sinusoidal pattern (see photo on the right). The streaks of light were the peak and trough levels of the sine wave and hence they were equidistant. It seems to be an interference pattern between the incident rays and the reflected rays. I did try to reproduce the pattern using another mirror instead of the vanity mirror. But I failed. The other mirror was thin compared to my thicker vanity mirror. This makes me believe that the incident rays are reflected by both the back (reflective coating) surface and also the front (glass face) surface causing a small phase shift. But I am open to other hypothesis. Any thoughts?
R&D / AI, Sr. Executive 20+ years at Siemens Healthcare | Led up to 50 People with $15M+ Budgets | Developed from Concept to Launch Products Used Globally by 200M People | Expertise in AI/ML and DFSS for Medical Systems
3 年Thanks all. Someone asked me what it means. Assuming this indeed is an interference pattern: 1. A ray of light is an electro-magnetic wave. Basically a wave whose amplitude changes as a sine wave (amplitude increases and decreases) as it propagates in a particular direction (Eg. similar to photo on the right). 2. When 2 such rays of light intersect, they interact depending on the phase angle at the point of intersection (A complete cycle is considered 360 deg starting/ending at 0 deg, positive peak is at 90 deg, negative peak/trough is at 270 deg) 3. The region where the 2 intersecting waves are in phase (meaning at same point in their 360 deg cycle), the amplitude gets added and you see a bright spot. 4. The region where the 2 intersecting waves are out of phase (meaning when one wave is at positive peak, the other is at negative peak), they 'cancel' each other showing a dark spot. 5. The net amplitude for other regions varies depending on the difference in phases of the 2 waves. 6. Consequently you get a pattern as I observed in the mirror. This is called an interference pattern. See picture of Young's double slit experiment. 7. Interference has many applications such as car muffler (sound waves), optical instruments etc.
Consultant - PMO ZS Associates
3 年Interesting
| Engineering | Marketing |
3 年Thanks Milind for sharing the insightful thoughts.