We encounter a large array of opacities every day, from the thin whites of clouds to the thick blues of skies, to the opaque greens of plants, and to the diluted artificial coloring in beverages. So,how much light is passing through an object? When light shines through an object the light is fully absorbed thus causing a shadow, or some light passes through tinted glass, and some gets blocked totally by the opacity of the object and becomes a faint shadow. A spectrophotometer is employed to measure the amount of light that a sample absorbs (David N. Blauch,2000). In this science project, we built a simple spectrophotometer from $50 using a cell phone and used it to investigate how visible light is absorbed by different water samples with different clarity.