ESL, Niveau avancé
Secrets in the Ocean
The seabed has presented a fertile hunting ground for marine archaeologists. On land, ancient artifacts may crumble, but in the sea ......... protect treasures that are thousands of years old.
Since the invention of surveying instruments such as magnetometers, revelations of ......... in the seabed can be found by divers.
Sonar was used to find remnants of Cleaopatra's palace, ancient statues and other treasures hidden under layers of silt. Marine archaeologist Frank Goddio created ......... maps to reveal what lay under the sediment.
As underwater exploration continued, Robert Ballard, a marine scientist, realized scuba divers and submersibles were limited in how far they could descend. His name has become ......... with pioneering the use of remote controlled vehicles for exploration.
Remote controlled vehicles allowed exploration at depths of 2500 ft in the Mediterranean. An ROVsent down to that depth used a robotic arm to retrieve 150 ......... containing wine, olive oil and fish sauce.
The use of a tethered remote controlled vehicle discovered sunken Mediterranean trading ships and changed historians' opinions of ancient sailors only venturing close to shore. New evidence disclosed these sailors could ......... across the sea.
Investigation into the wreck of the Titanic showed it did not have a huge gash caused by an iceberg. Rather the ship went down because of thin openings over the watertight holds, which were critical to its ..........
The use of remote vehicles has allowed the user to precisely ......... into dangerous areas beyond the capability of a diver.
The design of a slowly moving propeller prevents sand from being blown up from the seabed, which might ......... the controller's view.
As scuba divers can safely venture no deeper than 200 feet, the invention of remote vehicles was responsible for finding remarkably well preserved artifacts as well as ......... many theories about the cause of disasters.