Calcium. Jar of elemental calcium pellets. Calcium (Ca) is a reactive metallic element. It is classified as an alkaline earth metal, as are magnesium and barium. Although it is silver-white, it rapidly tarnishes on exposure to air, turning brown as seen here. Calcium metal is used in the manufacture of alloys and in casting. Its many compounds are important in industry. In the body, calcium is essential for the formation of bones and teeth, and calcium ions are important in blood clotting, regulation of the heartbeat, cell signalling and many other biochemical processes.
Science Photo Library was founded in 1981 by Michael Marten, one of the authors of "Worlds Within Worlds", a book exploring different ways to observe the universe - from electron micrographs, to images of earthrise taken from the Apollo spacecraft. When Marten started receiving requests for the beautiful images in the book, he had an idea of setting up Science Photo Library.
Since then, Science Photo Library has continued to work alongside world acclaimed photographers and the leading science and medical experts to provide a central source of the best science and specialist imagery available. Although the collection started with scientific images, it has grown to encompass all aspects of science and their impact on everyday life.
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If you're not happy with a purchase that you made on FineArtAmerica.com, for any reason, you can return it to us within 30 days of the order date. As soon as it arrives, we'll issue a full refund for the entire purchase price. Please note - Fine Art America does not reimburse the outgoing or return shipping charges unless the return is due to a defect in quality.