2015年10月4日 · You see reflections in water but not, say, sand, for the same reason you see your reflection in a polished piece of steel but not a rough-sanded piece of steel. All materials reflect light to some extent, but a rough surface scatters the reflected rays in all directions, so reflected images are blurred beyond recognition.

2019年11月7日 · According to Snell's law and Fresnel's equations, using IOR of 1.33 for water, my calculation of Fresnel's suggest the reflectivity of water at an angle of incidence of 0 is approx 0.02 (i.e. 2%). Googling turned up multiple references that quoted the same figure (suggesting my calculations are probably correct - or else multiple people are ...

The reason is that with these low angles, close to the reflective surface, the water or the table, the reflection occupies more and more "tiles", because they appear narrower and narrower, and smaller and smaller waves will produce the correct angles necessary to form the reflection.

For angles (between the normal direction and the light ray's direction) greater than the critical angle $$\theta_c=\arcsin(1.00/1.50) = 41.8^\circ$$ the photons can't get through and they will reflect from the glass-air boundary back to the glass and some of them will make it to the water (there may also be a total internal reflection when ...

The interface between the water and your mask obeys Snell's law which can be written, in the small angle approximation, as $$ n_1\theta_1=n_2\theta_2. $$ Since air has an index of refraction of essentially 1 and water has an index of refraction of 1.33 the angle from which the rays of light reach your eyes is larger than the angle they would in ...

2016年6月23日 · Reflection from still water can be high at grazing incidence, near sunrise or sunset, but the sunlight is significantly less intense at these times. You are far more likely to be in the pool around mid-day, when the sun is overhead. (Waves could bring some water near grazing incidence.) The largest reflection would come from white foam or sand.

If the problem with shallow water is that you see the walls and the bottom instead of only the reflection, I would just use a black bucket. Or somehow make bucket's inners black. Moreover a bucket is a bit unpractical in this case, just a really black tray with water should suffice. Another option is to make water black itself, like using coffee.

2020年8月3日 · An interface reflection (like the air-water interface) will occur for all wavelengths of light. Sunlight is partially polarized, but a polarizer will probably give enough contrast for your use case. It is possible to suppress reflections with an anti-reflective coating, but in your case, the coating would have to be applied to the surface of ...

2018年6月7日 · This mirroring of the car (or other objects) then tricks you into thinking the road is wet, because a wet street would also lead to a reflection. In addition, the air wobbles (i.e. density fluctuations), causing the mirror image to wobble as well, which adds to the illusion of water.

2019年1月20日 · All other things being equal a greater amount of reflection occurs at an air/glass interface than at an air/water interface because the difference in refractive index at the air(n=1)/glass(n=1.5) interface is greater than for the air(n=1)/water(n=1.33) interface.