Where does most ocean salt come from?

Rocks weathered on land and carried by rivers

Ocean Salinity Quiz – How Much Do You Really Know?

This ocean salinity quiz covers why seawater is salty, average salinity, the saltiest and freshest seas, the Dead Sea and Red Sea, salt and density, evaporation and rivers and how salt drives deep currents. Can you score 10 out of 10 on the salt in the sea?

Start Ocean Salinity Quiz

🎯 Daily Trivia Challenge • 🧠 10 Questions • ⏱️ 150 Seconds

Question 1 / 10 Time: 150s

Average
What is the average salinity of seawater?
Source
Where does most ocean salt come from?
Main
Which salt is most common in seawater?
Saltiest sea
Which sea is among the saltiest connected to the ocean?
Fresh
Which sea is unusually low in salt?
Dead Sea
Why can people float easily in the Dead Sea?
Density
How does salt affect seawater density?
Ice
What happens to salinity when sea ice forms?
Satellite
Which NASA mission measured sea surface salinity from space?
Brackish
What is brackish water?

Explanations: answer key for all 10 questions

Q1: What is the average salinity of seawater?
Answer: About 3.5%
That is about 35 grams per liter.
Q2: Where does most ocean salt come from?
Answer: Rocks weathered on land and carried by rivers
Undersea vents add some too.
Q3: Which salt is most common in seawater?
Answer: Sodium chloride
It is table salt.
Q4: Which sea is among the saltiest connected to the ocean?
Answer: Red Sea
High evaporation and little rain raise salt.
Q5: Which sea is unusually low in salt?
Answer: Baltic Sea
Many rivers and little evaporation dilute it.
Q6: Why can people float easily in the Dead Sea?
Answer: Its very salty water is dense
It is almost ten times saltier than the ocean.
Q7: How does salt affect seawater density?
Answer: More salt makes water denser
Dense water sinks.
Q8: What happens to salinity when sea ice forms?
Answer: Nearby water gets saltier
Salt is pushed out of the ice.
Q9: Which NASA mission measured sea surface salinity from space?
Answer: Aquarius
It ran from 2011 to 2015.
Q10: What is brackish water?
Answer: A mix of fresh and salt water
It is found in estuaries.

Ocean Salinity Quiz – Salt in the Sea

Seawater is salty because rivers carry dissolved minerals from weathered rocks into the ocean. When water evaporates, the salt stays behind. Over millions of years, the ocean has reached an average salinity of about 3.5%.

Salinity varies from place to place. Hot, dry regions like the Red Sea are saltier because evaporation is high, while the Baltic Sea is less salty because many rivers flow in. Inland lakes like the Dead Sea can be extremely salty.

Salt makes water denser, and cold, salty water sinks. This drives the deep ocean conveyor belt that moves heat around the world. Satellites and floats help scientists track salinity changes linked to climate.

What This Quiz Teaches

This quiz is for students learning about ocean salinity.

Why the sea is salty
What average salinity is
Which seas differ most
How salt affects density
How salinity drives currents

Did You Know?

If all ocean salt were spread on land, it would form a thick layer.
Seawater freezes below 0 °C.
Salinity is measured in practical salinity units.
The Great Salt Lake is very salty.
Rain lowers surface salinity.