Earth quiz

More questions about Earth

These visible examples show the question style. LearnClash turns the full topic into ranked duels and spaced repetition.

1. 1 Easy

   What is the circle of volcanoes around the Pacific Ocean?

   Answer: Ring of Fire

   Why: Despite the name it is a horseshoe, not a closed ring: about 40,000 kilometres long, with more than 450 volcanoes.

2. 2 Medium

   What gas is most common in Earth's atmosphere?

   Answer: Nitrogen

   Why: Nitrogen fills 78 percent of dry air, oxygen 21 percent and argon 0.93 percent, over twenty times the share held by carbon dioxide.

3. 3 Hard

   Which earthquake is the strongest ever recorded?

   Answer: Valdivia earthquake

   Why: At magnitude 9.5 the ground shook for about ten minutes, and the tsunami reached Hawaii in 15 hours and Japan in 22.

4. 4 Easy

   What geological structure forms where molten rock ruptures through Earth's crust?

   Answer: Volcano

   Why: The Pacific Ring of Fire holds more than 350 volcanoes active in historical times, plus about 90 percent of the world's earthquakes.

5. 5 Medium

   Which metal is the most abundant by mass in Earth's crust?

   Answer: aluminum

   Why: Aluminum makes up about 8% of the crust, yet in 1884 it cost about as much as silver: the Washington Monument's 100 ounce cap cost $225.

6. 6 Hard

   Which Mars-sized protoplanet collided with Earth to create the Moon?

   Answer: Theia

   Why: Theia is named after the Greek Titaness who bore the Moon goddess Selene, and two continent sized blobs deep in Earth's mantle may be her remains.