EVERYDAY SCIENCE

Detailed explanation-1: -Hess discovered that the oceans were shallower in the middle and identified the presence of Mid Ocean Ridges, raised above the surrounding generally flat sea floor (abyssal plain) by as much as 1.5 km.

Detailed explanation-2: -Harry Hess was a geologist and Navy submarine commander during World War II. Part of his mission had been to study the deepest parts of the ocean floor. In 1946 he had discovered that hundreds of flat-topped mountains, perhaps sunken islands, shape the Pacific floor.

Detailed explanation-3: -That enabled Hess to understand his ocean floor profiles in the Pacific. He realized that the Earth’s crust had been moving away on each side of oceanic ridges, down the Atlantic and Pacific oceans, that were long and volcanically active.

Detailed explanation-4: -Evidence of Sea Floor Spreading. Harry Hess’s hypothesis about seafloor spreading had collected several pieces of evidence to support the theory. This evidence was from the investigations of the molten material, seafloor drilling, radiometric age dating and fossil ages, and the magnetic stripes.

Detailed explanation-5: -Seafloor is youngest near the mid-ocean ridges and gets progressively older with distance from the ridge. Orange areas show the youngest seafloor. The oldest seafloor is near the edges of continents or deep sea trenches.