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Will a mountain last forever?
The Birth of Rocks Unit | Lesson 3 of 4

Will a mountain last forever?

The Birth of Rocks Unit | Lesson 3 of 4
Lesson narration:
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Discuss:
Here’s a close-up of one of the trees before they removed it. What do you think is going on here? What do you think happened to the pyramid?

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Discuss:

Has anyone ever told you not to put a can of soda in the freezer? Why do you think people say this?

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Discuss:

Can you think of some experiments you could do to figure out what happens to a rock as it tumbles downhill?

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🎉 That’s it for this lesson! How did it go?
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Activity Extension: More Sugar Shaking

In the Sugar Shake experiment, you are modeling a situation where identical rocks are tumbling together. You can see what happens when rocks of different types are bumping into each other by adding croutons (softer, more breakable “rocks”) and/or dried beans (harder, less breakable “rocks” to the container before you shake it.

How does the addition of other "rocks" affect the changes in the sugar cubes? How do the croutons and beans change with your shaking?

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Demonstration: The Mighty Beans

Use dried beans to demonstrate the power of seeds. Put beans into a paper or plastic cup until it’s about one quarter full. Add water until all the beans are completely covered. Set another cup on top, and add pennies (or other weights) so the cup presses down on the beans. Make a line with a marker to show the cup’s position.

Wait an hour, then check on your beans. (For the “after” photo, see next slide.)

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Demonstration: The Mighty Beans (after)

Dried beans are seeds — you can plant them and grow a bean plant. When you add water to dried dried beans, they start soaking up the water and swelling as they get ready to grow.

This is the first step in root wedging -- getting bigger and pushing against the surrounding rock. The beans in this cup lifted the weight of many pennies when they swelled.

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Activity: Plant Walk

Take your class for a walk in your schoolyard and look for plants that have taken root where they don’t belong. You may find grass growing in cracks in a sidewalk or plants sprouting between stones or bricks in a wall.

The roots of these plants are ever-so-slowly expanding the cracks in which they grow. Just as the plants on the side of a mountain break rocks apart, the plants in your schoolyard are breaking the sidewalk and the stone walls.

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Image & Video Credits

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Lesson Image
El Capitan by Octagon , used under CC BY
Exploration
Everest by Luca Galuzzi , used under CC BY-SA
space view by NASA
Halfdome by Scott Catron , used under CC BY-SA
Mt. San Jacinto by Wattewyl , used under CC BY
Great Pyramid of Giza by Wknight94 , used under CC BY-SA
Chichen Itza by Christine Zenino , used under CC BY
light brick wall by Titus Tscharntke
Complejo Danta by Ronyrocael , used under CC BY-SA
El Mirador by Geoff Gallice , used under CC BY
Copan ruins by Matthias Hiltner , used under CC BY
Puna lava flow by DVIDSHUB , used under CC BY
Annona Atemoya seeds by takoradee , used under CC BY-SA
cement texture by Titus Tscharntke
El Tigre pyramid by Dennis Jarvis , used under CC BY-SA
Temple of Nohoch Mul by Vin Crosbie , used under CC BY-ND
pavement by Simon Law , used under CC BY-SA
sidewalk & tree roots by Doug Caldwell , used under CC BY
cracked brick wall by debs-eye , used under CC BY
refrigerator by Juan de Vojníkov , used under CC BY-SA
soda can by Ryan McGilchrist , used under CC BY-SA
frozen soda can by William Brawley , used under CC BY
explosion in freezer by mrsparks , used under CC BY-SA
frozen bottle by baronsquirrel , used under CC BY
broken rock by Till Niermann , used under CC BY-SA
weathered rock by Natursicilia , used under CC BY-SA
rock parts by Lamiot , used under CC BY
Mount Hood by Thomas Shahan , used under CC BY
Mont Saint Honorat by Zil , used under CC BY-SA
jagged rocks by Peretz Partensky , used under CC BY-SA
Nuna Island by Kim Hansen , used under CC BY-SA
Activity
horses by Ben Salter , used under CC BY
pencil by Charm
Other
pebble beach by Paul Allison , used under CC BY-SA
Lesson narration:

Earth's Features & Processes

Weathering & Erosion

4-ESS1-1, 4-ESS2-1

Activity Prep

Print Prep

In this lesson, students will explore how solid rock breaks apart into smaller pieces through a process called weathering (including root-wedging and ice-wedging). In the activity, Sugar Shake, students use sugar cubes as a model for rocks. They perform an experiment with this model to understand the process of weathering and how this process explains why rocks at the tops of mountains are jagged, while those at the bottom are rounded.

Preview activity
Digital worksheets available
Teacher demo recommended

Students at home
Set up the activity and demonstrate over video conference. Students need the Sugar Shake Data worksheet (printed or digital) to record their observations.
Students at school
Set up containers with sugar cubes and demonstrate the activity while students make observations. Each student needs a Sugar Shake Data worksheet to record their observations.
Exploration

20 mins

Hands-On Activity