What can I conclude from the light on the plain water and on the soapy water?

If you add soap or detergent in water, the surface tension of water changes, the molecular bond of water becomes weaker. So, when light hits a plain water, it could either be reflected, or the water gets heated and evaporates, and then forms into gas.

Explanation:

Something like this?

the volume increases

that's what i got you can count the number of atoms