Chemical element element (by mass) making up Earth, while oxygen is the most common element in the Earth's crust. Chemical elements constitute all of the ordinary matter of the universe. However astronomical observations suggest that ordinary observable matter makes up only about 15% of the matter in the universe: the remainder is dark matter; the composition of this is unknown, but it is not composed of chemical elements. The two lightest elements, hydrogen and helium, were mostly formed in the Big Bang and are the most common elements in the universe. The next three elements (lithium, beryllium and boron) were formed mostly
Boiling liquid expanding vapor explosion Boiling liquid expanding vapor explosion A boiling liquid expanding vapor explosion (BLEVE, ) is an explosion caused by the rupture of a vessel containing a pressurized liquid that has reached temperatures above its boiling point. There are three characteristics of liquids which are relevant to the discussion of a BLEVE: Typically, a BLEVE starts with a container of liquid which is held above its normal, atmospheric-pressure boiling temperature. Many substances normally stored as liquids, such as CO, propane, and other similar industrial gases have boiling temperatures, at atmospheric pressure, far below room temperature. In the case of water, a BLEVE