Â­. Â­Dry ice is frozen carbon dioxide. A block of dry ice has a surface temperature of -109.3 degrees Fahrenheit (-78.5 degrees C). Dry ice also has the very nice feature of sublimation -- as it breaks down, it turns directly into carbon dioxide gas rather than a liquid.
The time for a broken collarbone to fully heal depends on the severity of the injury. In children, complete healing may take as little as three to six weeks. In adults, six to 16 weeks or more are often necessary for a collarbone to heal solidly.
A cracked or broken collarbone will be extremely painful. There may also be: 1  swelling or tenderness around the injured area. 2  bruising to the skin. 3  bleeding if the bone has damaged the tissue and skin (this is rare). 4  numbness or pins and needles if nerves in the arm are injured.