New aerogels are disclosed which comprise silica and at least one organic polymer having polar functional groups. Also disclosed are methods for making such aerogels and for making them as substantially transparent objects. In addition, gas detectors, liquid and gas absorbing objects, and optical devices made using these aerogels are disclosed. The present invention concerns optical elements which are substantially transparent and exhibit low refractive indices. The invention further relates to detectors of reactive and absorbate gases based on the physical changes exhibited by the aerogels upon reacting with or absorbing such gases. The present invention further concerns printable objects comprising these aerogels, specifically when the print media are imaged by the absorption of liquid and the spatial localization of pigments or dyes. The invention further concerns reactive gas absorbers comprising these aerogels and the catalytic function the aerogels serve to catalyze subsequent chemical reaction. Furthermore, the present invention concerns the absorption of chemical compounds from condensed states including liquid, critical and supercritical fluids.