Quiz template · Education
Ocean quiz questions and answers
20 questions on the ocean: how much of Earth it covers, the Challenger Deep, tides, coral, the Gulf Stream, sonar and the two men who reached the bottom.
Easy 20 questions 30 s each · about 16 min Checked against two sources
A geography and science round for a classroom, a youth group or a family that likes nature documentaries. It starts with the big numbers, how much of the planet is water and how deep it goes, then works through tides, currents, coral and the strange places where sunlight never reaches. Every answer is checked against two sources, most of them NOAA, the US ocean agency. Twenty questions take about 16 minutes.
How to run it
- Play it before a unit on oceans or climate and keep the scores. Play it again at the end of the unit and the class can see what it learned.
- Stop after question 11, the average depth. Ask the room to guess how far down a sunken ship would sit if it went down in open water, then show the answer. Most guesses are far too shallow.
- Questions 16 to 20 are app only and include the three hardest. Question 20, the depth of the Challenger Deep, is the tie-breaker.
Questions and answers
1Roughly how much of the Earth's surface is covered by ocean?Easy
- AAbout 29%
- BAbout 50%
- CAbout 71%
- DAbout 90%
Reveal answer
C. About 71%
NOAA puts it at more than 70 percent, and the usual figure is 71. That is why photos from space show a blue planet with the land in patches.
2The deepest known point in any ocean is called what?Easy
- AThe Challenger Deep
- BThe Puerto Rico Trench
- CThe Java Hole
- DThe Atlantis Basin
Reveal answer
A. The Challenger Deep
It sits at the southern end of the Mariana Trench in the western Pacific. The name comes from HMS Challenger, the British survey ship that first measured it in the 1870s.
3How many oceans does the United States, like most countries, now recognise?Easy
- AThree
- BFive
- CFour
- DSeven
Reveal answer
B. Five
The Pacific, Atlantic, Indian, Arctic and Southern. The Southern Ocean around Antarctica is the newest on the list, and all five are really one connected body of water.
4Which is the smallest of the five oceans?Easy
- AThe Indian Ocean
- BThe Southern Ocean
- CThe Atlantic Ocean
- DThe Arctic Ocean
Reveal answer
D. The Arctic Ocean
The Arctic Ocean is the smallest and shallowest of the five. Much of it is covered by sea ice for most of the year.
5What causes the tides?Easy
- AThe pull of the Moon and the Sun
- BThe wind
- CHeat from the Earth's core
- DThe spin of the ocean floor
Reveal answer
A. The pull of the Moon and the Sun
The Moon does most of the work because it is so close, and the Sun adds to it. When the two line up at new and full moon you get the biggest tides, called spring tides.
6The ocean that circles Antarctica is called what?Easy
- AThe Antarctic Sea
- BThe Polar Ocean
- CThe Southern Ocean
- DThe Ross Ocean
Reveal answer
C. The Southern Ocean
The US Board on Geographic Names takes it as everything south of 60 degrees south. It is the only ocean that runs right around the globe, with Antarctica in the middle.
7Coral reefs are built by what kind of living thing?Easy
- APlants
- BAnimals
- CFungi
- DBacteria
Reveal answer
B. Animals
Corals are colonies of tiny animals called polyps, each one building a hard cup of calcium carbonate. Over centuries those cups pile up into a reef.
8The Gulf Stream is a warm, fast current. In which ocean does it flow?Medium
- AThe Pacific
- BThe Indian
- CThe Atlantic
- DThe Arctic
Reveal answer
C. The Atlantic
It runs north along the coast of Florida, turns east off North Carolina and carries warm water across the North Atlantic towards Europe.
9About how much of seawater's weight is dissolved salt?Medium
- A0.5%
- B3.5%
- C10%
- D25%
Reveal answer
B. 3.5%
That is 35 parts per thousand. Most of the salt came from rocks on land, worn down by slightly acidic rain and carried to the sea by rivers over millions of years.
10The sunlit layer of the ocean, where most sea life lives, reaches down to about what depth?Medium
- A20 metres
- B2,000 metres
- C5,000 metres
- D200 metres
Reveal answer
D. 200 metres
Below about 200 metres there is too little light for plants to grow. Some light reaches about 1,000 metres on a clear day, and below that it is completely dark.
11What is the average depth of the ocean?Medium
- AAbout 370 metres
- BAbout 1,200 metres
- CAbout 3,700 metres
- DAbout 11,000 metres
Reveal answer
C. About 3,700 metres
NOAA gives 3,682 metres, about 12,080 feet. Most of the ocean floor is deep plain, a long way below the shallow shelves that line the continents.
12What usually sets off a tsunami?Medium
- AAn earthquake under the sea
- BA strong onshore wind
- CA full moon
- DA passing ship
Reveal answer
A. An earthquake under the sea
A sudden shift of the seafloor pushes the whole column of water above it, and the waves can cross an ocean in hours. Undersea volcanoes and landslides can start one too.
13Which sea in the Atlantic has no coastline at all, only currents for borders?Medium
- AThe Caribbean Sea
- BThe Sargasso Sea
- CThe Baltic Sea
- DThe Red Sea
Reveal answer
B. The Sargasso Sea
Currents circle it on every side, and it is named for the floating sargassum seaweed that gathers there. It is the only named sea with no land boundary.
14Ships map the seafloor by bouncing sound off it. What is the technology called?Easy
- ARadar
- BLidar
- CBarometry
- DSonar
Reveal answer
D. Sonar
Sonar sends out a ping and times the echo. Radar does a similar job with radio waves in the air, but radio does not travel far in water, so sound is what works below the surface.
15The highest tides in the world are in the Bay of Fundy. Which country is it in?Medium
- ACanada
- BNorway
- CChile
- DAustralia
Reveal answer
A. Canada
The bay sits between New Brunswick and Nova Scotia. The water can rise and fall by around 16 metres between low and high tide, and the funnel shape of the bay makes the swing bigger.
5 more questions in the full pack. Play all 20 live, free.
Get all 20 questions, ready to play live - free for 100 playersQuestions about this template
What age group is the oceans quiz for?
It works from about age 10 upwards. The first eight questions are easy and the hard ones sit at the end, so younger players stay in the game and older ones still get a challenge.
Can I play it live with a class?
Yes. Press Go live, show the PIN or QR code on the board and students join on their phones or tablets. The leaderboard appears after every question, and the free plan covers 100 players in a session.
Do students need to install an app?
No. They open the link or scan the code in a browser, type the PIN and a name, and play. Only the host needs a RiLiFi account.
Can I change the questions?
Yes. Use this template to make a copy, then rewrite any question, swap in local seas or rivers, or remove the ones your class has not covered yet.
Sources
Every answer shown here was checked against two sources, listed below. Links last checked 29 October 2026.
- Ocean - Wikipediaen.wikipedia.org
- How much water is in the ocean?oceanservice.noaa.gov
- Challenger Deep - Wikipediaen.wikipedia.org
- How deep is the ocean?oceanservice.noaa.gov
- How many oceans are there?oceanservice.noaa.gov
- Arctic Ocean - Wikipediaen.wikipedia.org
- What is the world's smallest ocean?oceanservice.noaa.gov
- Tide - Wikipediaen.wikipedia.org
- What are tides?oceanservice.noaa.gov
- Southern Ocean - Wikipediaen.wikipedia.org
- Coral reef - Wikipediaen.wikipedia.org
- Are corals animals or plants?oceanservice.noaa.gov
- Gulf Stream - Wikipediaen.wikipedia.org
- How fast is the Gulf Stream?oceanservice.noaa.gov
- Seawater - Wikipediaen.wikipedia.org
- Why is the ocean salty?oceanservice.noaa.gov
- Photic zone - Wikipediaen.wikipedia.org
- How far does light travel in the ocean?oceanservice.noaa.gov
- Tsunami - Wikipediaen.wikipedia.org
- What is a tsunami?oceanservice.noaa.gov
- Sargasso Sea - Wikipediaen.wikipedia.org
- What is the Sargasso Sea?oceanservice.noaa.gov
- Sonar - Wikipediaen.wikipedia.org
- What is sonar?oceanservice.noaa.gov
- Bay of Fundy - Wikipediaen.wikipedia.org
- Where is the highest tide?oceanservice.noaa.gov
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