# What is the best angle to see water

Sometimes when I clean my house, I miss some of the water since it seems invisible, but when I stand in different angle from the water I can see it clearly, whereas some angles offer partial transparency.

My question is from which angle is it best to observe the water? (I suppose it has to do with the angle of the sun, but what if I my light comes mainly from light bulbs?)

In addition, the reflectivity of the water increases with increasing angle of incidence which is captured in the figure below. If you stand directly above the water and the light bulb that you are trying to see is directly over your head (with a small offset), then the reflectivity of the water is very low at $\sim2\ \%$, and you may not notice the water. If you try to use a light at the side of the room so that the angle of incidence is large, then the water's reflectivity goes up significantly, and it is much easier to see.