Sattva is the observer, rajas is observation, and tamas is the thing to be observed. The moment the observer (sattva) touches the thing to be observed (tamas) via observation (the medium of rajas), that gives us experience.
In that experience, our awareness becomes materialized or crystallized. Experience is the precipitation or residue of awareness, so it is always of the past. Every experience nourishes ahamkara. The bigger the experience, the bigger the experiencer; the smaller the experience, the smaller the experiencer. If ahamkara does not identify with the experience, then awareness can remain in the present moment, becoming bliss.