Ocean Depths
1 / 15Deep sea knowledge, trenches, and marine science
15 quick questionsNo sign-upFree to playTap an answer below to begin ↓
What is the deepest known point in the world's oceans?
About Ocean Depths
Ocean Depths is a free general knowledge quiz with 15 multiple-choice questions with a mix of 7 medium, 6 easy, 2 hard questions. Deep sea knowledge, trenches, and marine science A typical run takes about 7 minutes, hints are always one tap away, and your streak ticks up the first time you finish a game on a given day.
A few sample questions
1. What is the deepest known point in the world's oceans?
Answer: Challenger Deep
Challenger Deep, located in the Mariana Trench in the western Pacific Ocean, reaches approximately 36,000 feet (about 11,000 meters) below sea level, making it the deepest known point on Earth.
2. Who was the first person to reach the bottom of the Mariana Trench in 1960?
Answer: Jacques Piccard and Don Walsh
Swiss oceanographer Jacques Piccard and U.S. Navy Lieutenant Don Walsh descended to the bottom of the Challenger Deep on January 23, 1960, in the bathyscaphe Trieste.
3. What percentage of the ocean floor has been mapped in detail?
Answer: About 25%
As of recent estimates, only about 25% of the ocean floor has been mapped to modern standards using high-resolution sonar. Much of the deep ocean remains unexplored and unmapped.
4. What is the name for the region of the ocean where sunlight cannot penetrate?
Answer: Aphotic zone
The aphotic zone (also called the midnight zone) is the part of the ocean where no sunlight reaches, generally below about 3,300 feet (1,000 meters). 'Aphotic' means 'without light.'
5. What phenomenon allows deep-sea creatures to produce their own light?
Answer: Bioluminescence
Bioluminescence is the production of light by living organisms through chemical reactions. About 76% of deep-sea creatures use bioluminescence to attract prey, find mates, or escape predators.
Things you'll learn along the way
- The Pacific Ocean is the deepest ocean with an average depth of about 14,040 feet (4,280 meters). It is also the largest and oldest of the world's ocean basins.
- Hydrothermal vents are often called black smokers because they emit dark plumes of superheated, mineral-rich water that looks like black smoke. They can reach temperatures above 700°F (370°C).
- The Great Barrier Reef off the coast of Australia is the largest structure made by living organisms. Stretching over 1,400 miles (2,300 km), it is built by billions of tiny coral polyps.
Frequently asked questions
What's a good follow-up after Ocean Depths?
If you enjoyed this general knowledge quiz, try the Daily Challenge — five rotating questions, refreshed every 24 hours, that count toward your streak. You can also use the Surprise Me button on the homepage to land on a different game type for variety.
Can I print Ocean Depths?
Yes — use the Print button at the top of the page for a clean question sheet, or "Print with Answers" to make an answer key. Printed sheets work well for group play at home, in a classroom, or at a senior center.
Will I lose my progress if I close the page?
Your overall progress — XP, streaks, and badges — is saved in your browser automatically. A quiz that's underway restarts if you leave mid-game, but at about 7 minutes, Ocean Depths fits comfortably in one sitting.
How many questions are in Ocean Depths?
Ocean Depths has 15 multiple-choice questions. Each one has four answer options and an explanation that appears after you answer, so you learn something even when you miss.
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