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Earth Science · Grades 6–8
Earth Science
Pick up any pebble. It has been places you will never go, and it can tell you about them.
The ground under your feet has been melted, squeezed, broken into sand, carried away by rivers, and turned back into stone. Not once, but over and over, for a very long time. Earth formed about 4.6 billion years ago, and its rocks are still being recycled today.
Geologists read rocks like a field notebook. Grab a pencil: by the end of the first unit you will be able to pick up a rock and ask, "Where have you been?"
What is Earth science?
Earth science is the study of our planet: its rocks and minerals, the ground that shifts and shakes, the water and air that wear it down, and the long history written in its layers. People who study rocks and the processes that shape them are called geologists.
Here is the surprising part: most of Earth's big changes happen far too slowly to watch. A grain of sand might take millions of years to become part of a rock. So geologists act like detectives. They look closely at the clues a rock holds today, such as the size of its crystals, its layers, and any fossils inside, and work out what must have happened to it.
You can do the same. A hand lens, a notebook, and good questions are the first tools of every field geologist.
Units
The first unit is ready to explore. More are being written now, and the ones below marked "Coming soon" are not ready yet.
- Live
Rocks and the Rock Cycle
What rocks and minerals are; the three rock families (igneous, sedimentary, and metamorphic) with specimen cards; the processes that turn one rock into another; and how James Hutton and Mary Anning read the rocks. Includes a hand-drawn rock cycle diagram, the Rock Cycle Journey game, and a quiz.
- Coming soon
Minerals and Crystals
How to tell minerals apart with simple tests for hardness, streak, and luster, and why crystals grow in their shapes.
- Coming soon
Weathering, Erosion, and Soil
How water, ice, wind, and living things break rock apart and move it, and how soil forms.
- Coming soon
Plate Tectonics
Why continents drift, where mountains and volcanoes come from, and what makes the ground shake.
- Coming soon
Fossils and Geologic Time
How fossils form, how layers of rock record time, and how scientists work out the age of a rock.
Field tools and reading
Everything below is part of the Rock Cycle unit. Jump straight to the part you need.
- Rock Cycle JourneyA keyboard-friendly game. Pick the processes that carry a rock from one form to another, in six missions.
- Rock cycle diagramA hand-drawn map of how magma, sediment, and the three rock families connect.
- Specimen cardsThirteen rocks, from granite to gneiss, each with how it forms and where you can see it.
- Quick quizEight questions with explanations, so you can check what you have learned.
How do we know?
Field notes
In June 1788 the Scottish geologist James Hutton took a boat along the coast east of Edinburgh with two friends, John Playfair and Sir James Hall. At Siccar Point they saw gray rock layers standing almost straight up, with flat red sandstone lying across their worn-down tops. Hutton realized the lower layers must have formed, been tipped up, and been worn away before the sandstone was even laid down. That would take an enormous amount of time. Earth had to be far older than most people then believed.
About twenty years later, on the south coast of England, a girl named Mary Anning was searching the crumbling cliffs of Lyme Regis for fossils. Her brother Joseph spotted the skull of a strange sea reptile, and Mary dug out the rest of its skeleton. The fossils she found in layers of limestone and shale helped convince scientists that Earth is very old and that animals can go extinct. You will meet both of them in the Rock Cycle unit.
About these lessons
Every unit is written for grades 6–8, with new words explained the first time they appear. Each page ends with its sources, so you can check the facts yourself. The games and quizzes work with a keyboard, a mouse, or a touch screen, and the lesson text is all there even if JavaScript is turned off. Best scores are saved only in your own browser.
Sources
- British Geological Survey, Discovering Geology (Earth formed about 4.6 billion years ago).
- Edinburgh Geological Society, Hutton's Unconformity.
- Scottish Geology Trust GeoGuide, Siccar Point.
- Natural History Museum, London, Mary Anning: the unsung hero of fossil discovery.
- The Geological Society of London, Lyme Regis beaches.
Credits
Jugami Earth Science is written by Mary, Jugami's Earth science teacher, named for the fossil hunter Mary Anning of Lyme Regis. Every illustration on this site is original, hand-coded SVG, and the share images are drawn in code. No photos, no ads, no trackers.