Why does melting ice speed up warming?

Dark water absorbs more sunlight than white ice

How does Antarctic sea ice differ from Arctic sea ice?

It mostly melts each summer and reforms in winter

Sea Ice Quiz: Places, People and Key Facts

This sea ice quiz covers how sea ice forms, Arctic and Antarctic sea ice, the difference between sea ice and icebergs, polar bears and seals, the Northwest Passage, satellite records and why Arctic ice is shrinking. Ten questions on places, people and key facts about frozen oceans.

Start Sea Ice Quiz

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

Question 1 / 10 Time: 150s

Formation
What is sea ice?
Salt
Is sea ice salty?
Temp
At about what temperature does seawater freeze?
Bears
Why do polar bears need sea ice?
Minimum
When does Arctic sea ice reach its smallest extent each year?
Trend
How has Arctic summer sea ice changed since 1979?
Albedo
Why does melting ice speed up warming?
Passage
Which Arctic sea route is opening as ice melts?
Antarctic
How does Antarctic sea ice differ from Arctic sea ice?
Pancake
What is pancake ice?

Explanations: answer key for all 10 questions

Q1: What is sea ice?
Answer: Frozen seawater
Icebergs come from glaciers instead.
Q2: Is sea ice salty?
Answer: Much less salty than seawater
Salt is pushed out as it freezes.
Q3: At about what temperature does seawater freeze?
Answer: About −1.8 °C
Salt lowers the freezing point.
Q4: Why do polar bears need sea ice?
Answer: To hunt seals
They wait at seal breathing holes.
Q5: When does Arctic sea ice reach its smallest extent each year?
Answer: September
It is largest in March.
Q6: How has Arctic summer sea ice changed since 1979?
Answer: It has declined sharply
Satellites track it daily.
Q7: Why does melting ice speed up warming?
Answer: Dark water absorbs more sunlight than white ice
This is the albedo feedback.
Q8: Which Arctic sea route is opening as ice melts?
Answer: Northwest Passage
Amundsen first sailed it in 1906.
Q9: How does Antarctic sea ice differ from Arctic sea ice?
Answer: It mostly melts each summer and reforms in winter
It surrounds a continent.
Q10: What is pancake ice?
Answer: Round pieces of young sea ice
Waves bump them into circles.

Sea Ice Quiz – Frozen Oceans

Sea ice forms when ocean water freezes, mostly in the Arctic and around Antarctica. It grows in winter and shrinks in summer, covering millions of square kilometers. Unlike icebergs, which break off glaciers, sea ice is frozen seawater.

Sea ice supports polar bears, seals, walruses and penguins, as well as algae that feed krill. It also reflects sunlight, helping keep the poles cool. When it melts, darker water absorbs more heat, speeding warming.

Satellites show Arctic summer sea ice has shrunk dramatically since 1979. This opens new shipping routes but threatens wildlife and Indigenous ways of life. Antarctic sea ice has also hit record lows in recent years.

What This Quiz Teaches

This quiz is for students learning about sea ice.

What sea ice is
Why it is less salty
Why polar bears need it
How it has changed
What albedo feedback is

Did You Know?

Antarctic sea ice reached a record low in 2023.
Brine channels in ice host tiny life.
Icebreakers clear paths for ships.
Multiyear ice is thicker.
Sea ice affects ocean currents.