Will a mountain last forever?

Mystery Science, Doug Peltz
Type Category
Instructional Materials
Activity , Experiment/Lab Activity , Lesson/Lesson Plan
This resource, vetted by NSTA curators, is provided to teachers along with suggested modifications to make it more in line with the vision of the NGSS. While not considered to be "fully aligned," the resources and expert recommendations provide teachers with concrete examples and expert guidance using the EQuIP rubric to adapted existing resources. Read more here.



In this mystery, 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, students  model the process of weathering that occurs when rocks tumble and crash into each other using sugar cubes in a container as an analogy. Classroom discussions and the activity lead students to discover that weathering is a process that changes the shape of the land.  To find the lesson, go to the second grade lessons under the heading: Birth of Rocks. This is mystery#3: Will a mountain last forever? Note: This resource is free for a limited time. A paid account is needed for unlimited access.

Intended Audience

Educator and learner
Educational Level
  • Grade 5
  • Grade 4
  • Grade 3
  • Grade 2
Access Restrictions

Free access with user action - The right to view and/or download material without financial barriers but users are required to register or experience some other low-barrier to use.

Performance Expectations

2-ESS1-1 Use information from several sources to provide evidence that Earth events can occur quickly or slowly.

Clarification Statement: Examples of events and timescales could include volcanic explosions and earthquakes, which happen quickly and erosion of rocks, which occurs slowly.

Assessment Boundary: Assessment does not include quantitative measurements of timescales.

This resource appears to be designed to build towards this performance expectation, though the resource developer has not explicitly stated so.

Comments about Including the Performance Expectation
Through the activity and videos, students use information and evidence to explain how weathering changes the shape of the earth. Class discussions should support explanations about what is happening, how, and why. Teachers will need to make sure to discuss whether the changes happened slowly or quickly.

Science and Engineering Practices

This resource is explicitly designed to build towards this science and engineering practice.

Comments about Including the Science and Engineering Practice
Students mimic slow changes to Earth materials caused by weathering by placing sugar cubes in a clear container with a tight lid. Students shake the container multiple times to simulate wind or water's movement of rocks smashing against mountains every day. As the sugar cubes hit each other, bits of the sugar cubes break off. Make sure to have the students color the edges of the cubes with markers before placing the cubes in the container. The students easily observe the changes to the sharp, straight colored edges as the weathering takes place to reveal smooth, rounded edges. Ask the students what happened as they shook the sugar cubes. (The sugar turns whatever color marker was used and the edges get more rounded.)

Disciplinary Core Ideas

This resource is explicitly designed to build towards this disciplinary core idea.

Comments about Including the Disciplinary Core Idea
The activity helps students see the changes that happen when rocks hit each other. Further discussions should include how water and wind move sand, pebbles, and smaller rocks to slowly break off bits of mountains, making them smoother and more rounded over millions of years. It would be helpful to show some examples of the pyramids in Africa and compare to the ones used in the video made by the Mayans. The teacher may consider bringing in rocks that have sharp edges and some with rounded edges and asking the students to try to explain why the rocks might be shaped differently.

Crosscutting Concepts

This resource is explicitly designed to build towards this crosscutting concept.

Comments about Including the Crosscutting Concept
Students will see quick changes to their sugar cubes, but the students must know that in real life, the changes take years to occur. This is good time to remind the students about the Mayan pyramids. It may be beneficial to help the students figure out though natural phenomenon around the neighborhood, how some earth materials change slowly and quickly. For example, sand at the beach changes shape quickly, and the materials made from granite change more slowly.

Resource Quality

  • Alignment to the Dimensions of the NGSS: In the activity, students model the process of weathering that occurs when rocks tumble and crash into each other using sugar cubes in a container using all three dimensions. Students make firsthand observation of the changes to the sugar cubes. Students share their learning about the changes through peer discussions and the activity sheet responses. Class discussion and the videos within the lesson help students make the connection between the sugar cube activity and the slow changes made to mountains and the pyramids by blowing sand, rocks, wind, and water.

  • Instructional Supports: The lesson focuses on supporting students to make sense of slow changes to the land by emphasizing weathering of mountains and pyramids. Students are asked to make observations, state their claims, and justify their thinking to their peers and the teacher about the changes made to the mountains, pyramids, and sidewalks. The sugar cube activity allows students to be actively engaged in the investigation to determine what happens when rocks knock against each other and against larger objects, but it is an analogy and some students may struggle to see the connection between sugar cubes and rocks. The activity sheet provides evidence of the student’s claim, evidence, and reasoning for the investigation’s results. Student’s apply their learning from the investigation to a real world situation of rocks tumbling down a hill to discover that the rocks at the bottom are smoother than the ones at the top due to weathering. To make this resource stronger, a student’s written ideas and drawings about weathering could be included in a science notebook to better gauge the student’s learning.

  • Monitoring Student Progress: The activity sheet assesses the student's understanding of the concept of weathering. Although no rubric for assessing is included, the student responses address the key points of the concept. Formative assessment occurs as students interact with peers and the teacher to the posed questions about how the pyramids and mountain shapes change.

  • Quality of Technological Interactivity: Students observe and comprehend the information provided in the videos. Opportunities to turn and talk with peers are built into the lesson to generate conversations about weathering concepts.