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Describe Rocks Like a NASA Scientist

1. Learn why we study geology on Earth and other planets
Geologists are scientists who study a planet's solid features, like soil, rocks, and minerals. There are all kinds of rocks and minerals that make up our planet – as well as the Moon, Mars, and other rocky worlds. By studying these features, we can learn more about how rocky worlds form and change over time.
About the image: NASA's Curiosity rover tests its drill on Mars in August 2014. Image credit: NASA/JPL-Caltech

2. Learn how we study geology on Earth and other planets
On Earth, geologists have the luxury of making observations and collecting rock samples in person. To study rocks and soil on other planets, like Mars, we have to rely on spacecraft that can use their cameras and tools to act as our eyes and hands.
For example, Mars rovers like Curiosity and Perseverance use cameras to send detailed pictures of the Martian surface back to us on Earth so we can explore from a distance. We then compare the images to known substances on Earth to better understand and theorize about how the Martian rocks, soil, and minerals formed.
About the image: The image above, captured by NASA's Curiosity rover on Mars, shows an outcropping – an area where ancient bedrock underneath the surface is exposed. Outcroppings on Earth are known to form as a result of running water and create gravel that's a similar size and shape. By comparing this image of Mars to similar features on Earth, geologists have been able to theorize that Mars might have also once had running water.
3. Practice describing rock samples
To classify rocks, we make observations that give us clues about how they formed. Here is some of the vocabulary geologists use to describe and classify rocks.
Geology Vocabulary

4. Take the Edible Rocks Quiz
A great way to practice classifying rocks is by describing the structures found inside different candy bars. Like rocks and soil, candy bars have features that offer clues about what they're made of and how they formed. Unlike with rocks, we can easily see inside candy bars by cutting them in half, creating what's called a cross section.
Take the quiz below to see if you can match these images of candy-bar cross-sections to the correct description. Click the View accuracy button after you submit your answers to see how you did.

5. Challenge yourself with the Real Rocks Quiz
Take the quiz below to see if you can match these images of real Earth and space rocks to the correct description. Click the View accuracy button after you submit your answers to see how you did.