Chemical garden Chemical garden A chemical garden is an experiment in chemistry usually performed by adding metal salts such as copper sulfate or cobalt(II) chloride to an aqueous solution of sodium silicate (otherwise known as waterglass). This results in growth of plant-like forms in minutes to hours. The chemical garden was first observed and described by Johann Rudolf Glauber in 1646. In its original form, the chemical garden involved the introduction of ferrous chloride (FeCl) crystals into a solution of potassium silicate (KSiO). The chemical garden relies on most transition metal silicates being insoluble in water and coloured. A metal salt such
Cobalt therapy Cobalt therapy Cobalt therapy or cobalt-60 therapy is the medical use of gamma rays from the radioisotope cobalt-60 to treat conditions such as cancer. Beginning in the 1950s, cobalt-60 was widely used in external beam radiotherapy (teletherapy) machines, which produced a beam of gamma rays which was directed into the patient's body to kill tumor tissue. Because these "cobalt machines" were expensive and required specialist support, they were often housed in "cobalt units". Cobalt therapy was a revolutionary advance in radiotherapy in the post-World War II period but is now being replaced by other technologies such as linear accelerators. Before