Ocean Mysteries
More than this percent of Earth is covered by ocean.
70 percent
device uses sound waves to measure ocean depth.
sonar
Scientists found strange animals living near these underwater volcanic openings.
vents
Accurate maps help these large vessels avoid hazards.
ships
First step in sonar mapping: a ship releases this.
sound pulse
Scientists have carefully mapped only a small part of this.
the seafloor
A sonar pulse returns to the ship as this.
echo
Instead of sunlight, these animals used this for energy.
chemicals from Earth’s crust
Maps help scientists better predict these ground-shaking events.
earthquakes
Second sonar step: the sound strikes this
ocean floor
This mountain on land is shorter than some underwater mountains.
Mount Everest
These vehicles were created because divers could not go deep enough.
robotic vehicles or submersibles
The ocean floor looked like this fruit peel.
orange peel
Maps help locate important natural
protected
Third sonar step: the sound returns as this.
echo
Early sailors wrongly believed the ocean floor looked like this.
flat
These in space helped finish the mapping puzzle.
satellites
Sonar revealed underwater mountains and these deep low areas.
trenches
The author says exploring the ocean is not optional but this.
essential
Fourth sonar step: this machine calculates depth.
Computer
This makes it hard for light to travel far underwater.
water
Scientists combine satellite data, sonar readings, and these to make one global map.
robot images
This scientific understanding changed after vent animals were found.
life can exist
Maps reveal habitats that must be this
protected
This process had to be repeated thousands of times to create maps
Sonar mapping