Pebbles, Sand and Silt / Investigation 1: / First Rocks
How This Investigation Fits Within the Concept and Lesson Map:
Through observation students will sort and group (classify) rocks based on their properties.
Overarching Question(s) for the Whole Investigation
Do different rocks share some of the same properties?

How People Learn #1 Preconceptions

Eliciting Student Ideas:
Use the modified “Friends Rock Probe” for uncovering student prior ideas before beginning Investigation 1. Students will complete this individually and then discuss as a class. Students will record their current thinking in their science notebooks using the probe as an outline for their written response. By having students complete this in pen initially, they cannot change their writing later when asked to reflect.
Common Student Preconceptions:
“... rocks had to be large, heavy and jagged.” (Driver,2002)
“rocks are made of only one substance” (Driver, 2002)
Rocks are unchanging. (Learner.Org)
All rocks are grey and hard. Carre & Ovens, 2002)

How People Learn #2 Facts/Concepts/Knowledge

WA State Content Standards “Science Domains” (EALR 4)
K-1 ES2B / Earth materials include solid rocks, sand, soil, and water. These materials have different observable physical properties.
2-3 PS2A / Objects have properties, including size, weight, hardness, color, shape, texture, and magnetism. Unknown substances can sometimes be identified by their properties.
WA State Science Standards “Crosscutting Concepts and Abilities” (EALRs1-3)
2-3 INQF / Scientists develop explanations, using observations (evidence) and what they already know about the world. Explanations should be based on evidence from investigations.
2-3 INQD / Simple instruments, such as magnifiers, thermometers, and rulers provide more information than scientists can obtain using only their unaided senses.
2-3 INQC / Inferences are based on observations.
Key Understandings For the Teacher:
The word of this investigation is PROPERTIES (Essential attributes shared by all members of a group. ) This word should be used and modeled as frequently as possible with the students. Observations of properties are linked to student prior knowledge.Students are asked to observe the rocks’ properties, to describe the rocks’ properties, and to sort the rocks based on their properties. Asking them to examine and think about properties of the rocks that can be measured or described helps students examine materials the way a scientist does.

How People Learn #3 Metacognition

Metacognition: How did my thinking change? What caused the change? How did I come to believe this?
After completing Investigation 1, students should review their initial ideas from the probe and notebook entry, as well as their ideas from each part of Investigation 1 and reflect on how their ideas have changed. Students will likely need support for this kind of thinking at this time, explicitly connecting back to their preconceptions.
Example: “Look back at your notebook entry about the “Friends Probe,” reread it, and check to see if you still agree with what you wrote. Do you want to add or change any ideas?”
Example: “Here’s a new copy of the “Friends Probe” you filled out last week. Complete the probe again, compare the two, and write about your thinking. What thinking has stayed the same, and describe how some of your ideas have changed?”
Suggested Assessments for Student Understanding:
There are several opportunities within the FOSS curriculum to find out what students are thinking in this Investigation. Look for pre-conceptions in student work that have surfaced or changed.
Part 3: Students write about a rock (Rock Record Sheet page 16). You are looking for students to include several properties (color, shape, size, etc.) of that rock.
Part 4: While students are working on sorting games, the teacher should conduct 30-second interviews (page 24) with students to see that they are sorting using a variety of properties.
Part 5: As students share rocks for the collection, pay attention to the descriptions they use and notice if they are able to describe using several properties.

Additional Information

Materials and Student Management
Part 1: If students start by rubbing the basalt (dark gray) against other rocks first they will not see that the basalt can also be ground. So students should rub like rocks together first.
Part 1: The basalt, scoria, and tuff rocks are considered “permanent” parts of this kit and are not replaced. If you notice a student having too much success at grinding the rocks into dust, you may want to emphasize careful handling of lab samples.
Part 1: Guide students to infer that some rocks are harder than others.
Part 1: Show students how to use hand lenses in the first Part 1 lesson.
Part 2: Make an index card with the questions on page 15 of Investigation 1 to carry with you. Use as prompts to guide student observations.
Part 2: When students are completing the Rock Record sheets, use the photo set of the rocks * instead of asking students to draw them. They are more accurate and it is difficult to show differences when drawing the rocks.
Part 4: This is an important part because the students will sort in the obvious ways first and the more they sort, the more properties they may notice. It also offers an excellent time for the teacher to interview students.
Part 5: Teachers may want to have students begin bringing rocks during the other parts of this investigation so it does not take so long to make the rock collection.
Part 5 Read FOSS Science Story Exploring Rocks after completing the Part 5.
Timing Considerations
FOSS recommends setting up a center area where students are able to continue working with the rocks and other tools of the Investigation. This allows students to try many ways to sort and find properties of rocks beyond the time allotted for science.
If students begin bringing rocks for the rock collection before Part 5, the collection will be ready for Part 5.
Citations for Student Preconceptions:
R. Driver et al., 2002. Making Sense of Secondary Science. Routledge/Falmners, New York.
Learner.Org: Earth & Space Science.
Carre & Ovens. 2002. Science 7-11. Taylor & Francis, London.