Earth Science Quiz
Rocks, minerals, plate tectonics and fossils: 15 questions on the planet beneath your feet.
Roughly how old is planet Earth?
Got a hunch? Pick the answer that feels right.
4.5 billion years
Radiometric dating of meteorites and the oldest Earth minerals puts the planet's age at about 4.54 billion years, with the solar system forming from a collapsing cloud of gas and dust.
The oldest known Earth material, zircon crystals from Western Australia, dates to about 4.4 billion years, only a little younger than the planet itself.
Which type of rock forms when molten magma or lava cools and hardens?
Got a hunch? Pick the answer that feels right.
Igneous
Igneous rock is born from fire: granite forms when magma cools slowly underground, while basalt forms when lava cools quickly at the surface, which is why basalt has much smaller crystals.
Most of the ocean floor is made of basalt, making igneous rock by far the most common rock in Earth's crust.
Which mineral sits at 10, the very top of the Mohs hardness scale?
Got a hunch? Pick the answer that feels right.
Diamond
The Mohs scale ranks minerals by which can scratch which, from talc at 1 to diamond at 10, and diamond's rigid lattice of carbon atoms makes it the hardest natural mineral.
Corundum, at 9 on the scale, is the mineral behind both rubies and sapphires, which differ only in their trace impurities.
What instrument records the ground shaking produced by an earthquake?
Got a hunch? Pick the answer that feels right.
Seismograph
A seismograph records the vibrations that travel through the Earth as seismic waves, and the resulting trace lets scientists work out an earthquake's location and magnitude.
The Richter scale has largely been replaced by the moment magnitude scale, which better measures the energy released by very large earthquakes.
Which type of rock forms when sand grains are buried, compacted and cemented together?
Got a hunch? Pick the answer that feels right.
Sandstone
Sandstone is a sedimentary rock made of sand sized grains, usually quartz, that were buried, squeezed and glued together by minerals over millions of years.
Much of the red rock of the American Southwest, including the walls of Arches and Zion, is sandstone stained by iron oxide.
What is the name of the supercontinent that existed about 300 million years ago?
Got a hunch? Pick the answer that feels right.
Pangaea
Pangaea assembled around 300 million years ago and began breaking apart about 200 million years ago, first into Laurasia and Gondwana and eventually into the continents we recognise today.
The name comes from Greek words meaning all the Earth, and the single ocean that surrounded it is called Panthalassa.
Fossils are almost always found in which type of rock?
Got a hunch? Pick the answer that feels right.
Sedimentary
Sedimentary rock forms as layers of mud, sand and shells settle and compact, gently burying dead organisms, whereas the heat of igneous and metamorphic processes destroys most remains.
Limestone, sandstone and shale are the classic fossil bearing rocks, which is why fossil hunters head for cliffs and quarries made of them.
Marble is the metamorphic form of which rock?
Got a hunch? Pick the answer that feels right.
Limestone
When limestone is buried and subjected to heat and pressure, its calcite recrystallises into the interlocking crystals of marble, which is why pure marble is white and takes a polish.
Michelangelo's David was carved from Carrara marble quarried in Tuscany, a source that has been worked since Roman times.
In a limestone cave, what is the name of the formation that hangs down from the ceiling?
Got a hunch? Pick the answer that feels right.
Stalactite
Stalactites hang from cave ceilings as dripping water deposits calcium carbonate, growing downwards a few millimetres per century. Stalagmites are their partners rising from the floor.
A classic memory trick: stalactites hold on tight to the ceiling, while stalagmites might one day reach it.
Which river carved the Grand Canyon in Arizona?
Got a hunch? Pick the answer that feels right.
Colorado River
The Colorado River has been cutting down through the rock layers of the Colorado Plateau for about five to six million years, exposing nearly two billion years of Earth's history in the canyon walls.
At its deepest the Grand Canyon drops more than 1,800 metres (6,000 feet) from rim to river.
Which layer of the Earth is the thickest?
Got a hunch? Pick the answer that feels right.
Mantle
The mantle extends about 2,900 km (1,800 miles) below the crust to the top of the core and accounts for roughly 84 percent of Earth's volume, far more than any other layer.
The crust is thinnest beneath the oceans, where it can be only about 5 to 10 km (3 to 6 miles) thick.
Which scientist proposed the theory of continental drift in 1912?
Got a hunch? Pick the answer that feels right.
Alfred Wegener
Alfred Wegener, a meteorologist, argued in 1912 that the continents had once been joined and had drifted apart, pointing to matching coastlines and fossils on opposite sides of the Atlantic.
Wegener's idea was widely ridiculed until the 1960s, when seafloor spreading finally provided the mechanism he had lacked.
The San Andreas Fault in California is an example of which type of plate boundary?
Got a hunch? Pick the answer that feels right.
Transform
At a transform boundary two plates slide horizontally past each other, and along the San Andreas Fault the Pacific Plate grinds north-west past the North American Plate.
The two plates move past each other at roughly 3 to 5 cm (1 to 2 inches) a year, about the rate at which fingernails grow.
What is the name for the fan shaped deposit of sediment that forms where a river enters the sea?
Got a hunch? Pick the answer that feels right.
Delta
A delta forms where a river slows as it meets a lake or sea and drops the sediment it carries, building new land such as the Nile and Mississippi deltas.
The name comes from the Greek letter delta, whose triangular shape resembles the Nile delta as drawn on ancient maps.
The Mohorovičić discontinuity, known as the Moho, marks the boundary between which two layers of the Earth?
Got a hunch? Pick the answer that feels right.
Crust and mantle
Croatian seismologist Andrija Mohorovičić identified the boundary in 1909 after noticing that earthquake waves suddenly speed up at the base of the crust where it meets the denser mantle.
Project Mohole, a 1960s American attempt to drill through the crust to the Moho, was cancelled before it got anywhere close.
Your results
More to explore
All Science quizzes →About the Earth Science Quiz
Earth is about 4.5 billion years old, its mantle makes up roughly 84 percent of the planet's volume, and the Mid-Atlantic Ridge is pulling Europe and North America apart by a few centimetres every year. Geology moves slowly, but it has shaped everything from the Grand Canyon to the Himalayas, and every rock you pick up has a story.
These 15 questions cover the three rock types, the Mohs hardness scale, the layers of the Earth, plate boundaries, earthquakes, caves and fossils, finishing with a couple of questions that will test anyone who paid attention in geography class. It suits students revising earth science, curious hikers and anyone who has ever wondered what is really under their feet.
You will find 15 multiple choice questions here, each with four options. Difficulty: Medium. Most people finish in about 6 minutes, and every answer comes with a short explanation and one extra fact worth keeping.
How to play
Read the question and pick one of the four answers. The correct answer is revealed straight away with a short explanation, then press Next question to keep going. At the end you get your score out of 15 and a full review of your round. Play again any time and the questions arrive in a fresh order. There is no timer and no account.
Good to know before you play
What topics does this earth science quiz cover?
It covers rock types, minerals and the Mohs scale, the layers of the Earth, plate tectonics, earthquakes, volcanoes, erosion, caves and where fossils form.
What are the three main types of rock?
Igneous rock forms from cooled magma or lava, sedimentary rock from compressed layers of sediment, and metamorphic rock when existing rock is changed by heat and pressure.
Is this quiz suitable for school students?
Yes. The early questions match middle school earth science, while the later ones stretch to high school level topics such as plate boundaries and the Moho.
Answer key: all 15 questions with explanations
- Roughly how old is planet Earth?
4.5 billion years Radiometric dating of meteorites and the oldest Earth minerals puts the planet's age at about 4.54 billion years, with the solar system forming from a collapsing cloud of gas and dust. The oldest known Earth material, zircon crystals from Western Australia, dates to about 4.4 billion years, only a little younger than the planet itself. - Which type of rock forms when molten magma or lava cools and hardens?
Igneous Igneous rock is born from fire: granite forms when magma cools slowly underground, while basalt forms when lava cools quickly at the surface, which is why basalt has much smaller crystals. Most of the ocean floor is made of basalt, making igneous rock by far the most common rock in Earth's crust. - Which mineral sits at 10, the very top of the Mohs hardness scale?
Diamond The Mohs scale ranks minerals by which can scratch which, from talc at 1 to diamond at 10, and diamond's rigid lattice of carbon atoms makes it the hardest natural mineral. Corundum, at 9 on the scale, is the mineral behind both rubies and sapphires, which differ only in their trace impurities. - What instrument records the ground shaking produced by an earthquake?
Seismograph A seismograph records the vibrations that travel through the Earth as seismic waves, and the resulting trace lets scientists work out an earthquake's location and magnitude. The Richter scale has largely been replaced by the moment magnitude scale, which better measures the energy released by very large earthquakes. - Which type of rock forms when sand grains are buried, compacted and cemented together?
Sandstone Sandstone is a sedimentary rock made of sand sized grains, usually quartz, that were buried, squeezed and glued together by minerals over millions of years. Much of the red rock of the American Southwest, including the walls of Arches and Zion, is sandstone stained by iron oxide. - What is the name of the supercontinent that existed about 300 million years ago?
Pangaea Pangaea assembled around 300 million years ago and began breaking apart about 200 million years ago, first into Laurasia and Gondwana and eventually into the continents we recognise today. The name comes from Greek words meaning all the Earth, and the single ocean that surrounded it is called Panthalassa. - Fossils are almost always found in which type of rock?
Sedimentary Sedimentary rock forms as layers of mud, sand and shells settle and compact, gently burying dead organisms, whereas the heat of igneous and metamorphic processes destroys most remains. Limestone, sandstone and shale are the classic fossil bearing rocks, which is why fossil hunters head for cliffs and quarries made of them. - Marble is the metamorphic form of which rock?
Limestone When limestone is buried and subjected to heat and pressure, its calcite recrystallises into the interlocking crystals of marble, which is why pure marble is white and takes a polish. Michelangelo's David was carved from Carrara marble quarried in Tuscany, a source that has been worked since Roman times. - In a limestone cave, what is the name of the formation that hangs down from the ceiling?
Stalactite Stalactites hang from cave ceilings as dripping water deposits calcium carbonate, growing downwards a few millimetres per century. Stalagmites are their partners rising from the floor. A classic memory trick: stalactites hold on tight to the ceiling, while stalagmites might one day reach it. - Which river carved the Grand Canyon in Arizona?
Colorado River The Colorado River has been cutting down through the rock layers of the Colorado Plateau for about five to six million years, exposing nearly two billion years of Earth's history in the canyon walls. At its deepest the Grand Canyon drops more than 1,800 metres (6,000 feet) from rim to river. - Which layer of the Earth is the thickest?
Mantle The mantle extends about 2,900 km (1,800 miles) below the crust to the top of the core and accounts for roughly 84 percent of Earth's volume, far more than any other layer. The crust is thinnest beneath the oceans, where it can be only about 5 to 10 km (3 to 6 miles) thick. - Which scientist proposed the theory of continental drift in 1912?
Alfred Wegener Alfred Wegener, a meteorologist, argued in 1912 that the continents had once been joined and had drifted apart, pointing to matching coastlines and fossils on opposite sides of the Atlantic. Wegener's idea was widely ridiculed until the 1960s, when seafloor spreading finally provided the mechanism he had lacked. - The San Andreas Fault in California is an example of which type of plate boundary?
Transform At a transform boundary two plates slide horizontally past each other, and along the San Andreas Fault the Pacific Plate grinds north-west past the North American Plate. The two plates move past each other at roughly 3 to 5 cm (1 to 2 inches) a year, about the rate at which fingernails grow. - What is the name for the fan shaped deposit of sediment that forms where a river enters the sea?
Delta A delta forms where a river slows as it meets a lake or sea and drops the sediment it carries, building new land such as the Nile and Mississippi deltas. The name comes from the Greek letter delta, whose triangular shape resembles the Nile delta as drawn on ancient maps. - The Mohorovičić discontinuity, known as the Moho, marks the boundary between which two layers of the Earth?
Crust and mantle Croatian seismologist Andrija Mohorovičić identified the boundary in 1909 after noticing that earthquake waves suddenly speed up at the base of the crust where it meets the denser mantle. Project Mohole, a 1960s American attempt to drill through the crust to the Moho, was cancelled before it got anywhere close.
Browse other categories
Every category has its own quizzes, each with instant explanations.