PAUL RAPSON / SCIENCE PHOTO LIBRARY PAUL RAPSON / SCIENCE PHOTO LIBRARY
Packets of silica gel. Silica gel is a granular form of silica, synthetically manufactured from sodium silicate. It has an extremely high porosity, making it a highly effective adsorbent material. The large internal surface area enables each granule to attract and hold moisture through physical adsorbtion and capillary condensation. Packaged in a semi-permeable packet, silica gel is used as a desiccant to keep a variety of packaged goods dry. Although silica gel is inert and non-toxic, indicator substances are often added to it which change colour when moist. These substances are often toxic which is why the packets are usually labelled as such.
Model release not required. Property release not required.