Alexander Oparin, a Russian scientist, first put forth the idea that life on Earth could have formed from non-organic, inanimate molecules; this is called the Abiogenesis Theory. The simple elements contained in the Earth's early reducing atmosphere initially had only simple chemical interactions, and it was only with time and constant combining of elements that more complex molecules began to form. Oparin theorized that organic life must have sprung from inorganic materials because, at a molecular level, there is no difference between organic and inorganic. Oparin thought that since environmental reactions can break up and affect chemical interactions, the developing complex organic molecules must have had a way to isolate themselves until the reactions were complete. He called this a bubble theory, and called these non-cell simple structures protobionts. This theory has been expanded by many other scientists. One of the common scenarios is for air bubbles in the oceans and lakes to concentrate various developing chemicals; as the water concentrates on shore from waves, the bubbles combine and the reactions become more complex. This allows for organic life's dependence on water, as well as condensing hydrophilic compounds which would keep the bubbles intact for a longer period of time; the longer the bubble remains intact, the more interactions occur inside.