Maps, compasses, astrolabes, and calipers are among the early tools used by ocean navigators. In the modern era, these tools have been largely replaced by electronic and technological equivalents. Despite these early beginnings, it would take many centuries before global navigation at sea became possible.
Radon for Children. Harmful Effects of Radon. Radon is the second leading cause of lung cancer (diagram to the right) and a serious public health concern. The primary adverse health effect associated with chronic exposure to radon is lung cancer (typically bronchogenic): -squamous cell carcinoma. -small cell carcinoma.
Radon - Rn. Chemical properties of radon - Health effects of radon - Environmental effects of radon. Radon. Radon is colorless at standard temperature and pressure and it is the most dense gas known. At temperature below it's freezing point is has a brilliant yellow phosphorescence.