rolling and sliding: how does surface affect moving...

Rolling and Sliding: How DoesSurface Affect Moving Objects?

We have been investigating the ideas of motion happening allaround us in the classroom and in the environment, and wehave been talking about friction and energy. For this task, youwill blow through a straw to move a variety of objects (solids)across a smooth surface (desk) and a rougher surface (rug).You will observe how the objects move. Do they roll? Do theyslide? Or do they roll and slide? When we finish, you will beasked to share anything you noticed about using the differentsurfaces.

1 of 20Rolling and Sliding: How Does Surface Affect Moving Objects?

Copyright 2007, Exemplars, Inc. All rights reserved.

Rolling and Sliding: How Does Surface Affect MovingObjects?

Suggested Grade Span

K–2

Task

We have been investigating the ideas of motion happening all around us in the classroom andin the environment, and we have been talking about friction and energy. For this task, you willblow through a straw to move a variety of objects (solids) across a smooth surface (desk) and arougher surface (rug). You will observe how the objects move. Do they roll? Do they slide? Ordo they roll and slide? When we finish, you will be asked to share anything you noticed aboutusing the different surfaces.

Big Ideas and Unifying Concepts

Cause and effectDesign

Physical Science Concepts

Motion and forcesProperties of matter

Design Technology Concepts

Design constraints and advantagesUse of tools

Mathematics Concepts

CountingData collection, organization and analysisMeasurement

Time Required for the Task

Approximately 45–60 minutes (suggest using two periods during the same week).



Context

The first and second graders have been connecting the idea of motion with work and play indaily family routines. They have been investigating a variety of ways in which objects (solids)can be moved on different surfaces in the classroom. They have observed and tested pushing,pulling, twisting, bending, bouncing, rolling, sliding and blowing different objects. They havealso been introduced to the concept of friction and how it affects objects in motion. They will usetheir prior knowledge about how different objects can be affected by friction, changes insurfaces and the force exerted on the object.

What the Task Accomplishes

This task provides opportunities for conceptual understanding of friction and how friction isrelated to a variety of familiar surfaces existing in the school and home environment. Itreinforces and assesses the skills and knowledge the students have acquired concerning themotion of objects on different surfaces. The task extends understanding about how to usedifferent kinds of energy to make things move. Students communicate about the physicalproperties of shapes and surfaces and may make more global connections about materialsfound in nature compared with human-made materials that can stretch, bounce or bend.

How the Student Will Investigate

The children were actively and eagerly involved in this task because it was very student-directed. I provided sharing bins with a variety of objects to initiate their investigation, butstudents were encouraged to seek out any objects around the room or items from home to test.On the first day, children were asked to begin the investigation on a smooth surface (desks ortables) and test at least six objects by blowing them with straws. It is important to discuss thatfair testing requires that they blow the objects in the same way each time. It is also important tohave them blow gently to avoid anyone hyperventilating.

The first page of the recording sheet has three parts. Part one involves illustrating and labelingeach object to be tested. Part two asks for a prediction with a symbol to indicate whether theobject might roll or slide across the surface. Part three has two columns to record the finalresults using symbols and words. At the bottom of each page there is additional space forchildren to explain their conclusions.

On the second day, students were asked to repeat the activity with the same objects, now usingthe rug surface. Many of my children were curious about using some different objects thesecond day, which would alter the controlled variables. This is another opportunity to talk aboutfair testing: using the same objects, applying the same kind of blowing forces, and recording inthe same way. The variable that changes is the surface. Further testing, with new objects, is avalid way that scientists test and retest conclusions from earlier investigations and should beencouraged.



During the investigation, the teacher needs to move about the room and include time to allowsome students not as confident of their writing skills to dictate ideas and scientific observationsto share.

Interdisciplinary Links and Extensions

ScienceAn alternative approach to this task would be to test each object on both surfaces before goingon. This might help the Novice and Apprentice to better see comparisons between surfaces. Anextension from this activity might be to observe how hard students need to blow the object tomove it the same distance across different surfaces. Attach different objects to simple springscales and pull objects across the different surfaces so that students can see the amount offorce/effort needed to do so. Provide a wide variety of balls for the children to create a test todetermine why and how some balls bounce better than others on different surfaces. Provide thechildren with straws and search the room for objects to sort that they think will blow easily orsomewhat harder or will not move at all. If also studying simple machines, construct a wind carto take outside and investigate the strengths and weaknesses of its construction and movementon different surfaces. Make connections to different surfaces when introducing a unit of studyon the five senses.

Social StudiesResearch how people have used different kinds of energy to make things move in differentcultures. Discuss why some cultures still use the same tools while others have developed andrefined theirs. Ask students to investigate how people move heavy objects across differentsurfaces in the desert, arctic, swamps and/or forests. Have students design a way to move astack of books or heavy object across different surfaces (cloth, board, piece of cardboard,hands).

LiteracyIntegrating a variety of fiction and nonfiction books with each science unit helps children makeconnections with stories, writing and communicating while exploring scientific concepts. Youmight ask the students to list the steps of how to make an object move, such as by winding up atoy, blowing up a balloon, pulling a wagon or sliding on a sled. Partners might write a storyabout a favorite windup toy. Cooperative groups might illustrate and write about a new objectthat moves and performs a useful chore. Read a variety of poems from collections by ShelSilverstein or Jack Prelutsky for humorous writing about inventions or about creations bychildren to help them get out of chores.

Some of the books that you might use are:

• The Red Balloon, by Albert Lamorisse• Corduroy, by Don Freeman• Emma Bean, by Jean Van Leeuwen• Alexander and the Wind-Up Mouse, by Leo Lionni• Lights! Camera! Action!: How a Movie Is Made, by Gail Gibbons



• Making Things Move, by Neil Ardley• Force and Movement, by Barbara Taylor

MathematicsHave students measure how far each object moved, first on a smooth surface and then on arough one. This could be done with ramps of the same height to control the variable of force.Ask partners to construct a chart for 20 objects selected from the classroom and graph theirtype of movements (objects that roll, slide, bounce, twist, etc.). Predict and count how manytimes different balls will bounce on different surfaces before they stop and/or how far they willroll across different surfaces. Use the book Math Curse, by Jon Scieszka which has veryengaging illustrations, to integrate a variety of problem-solving extensions and everydayproblems for children.

Art/Music/MovementAsk the children to use their bodies to demonstrate the movements different balls can makewhen rolling across rough, bumpy or smooth surfaces. Incorporate mime and music to illustratea story about a ball and its use. Use the resource Piggy Back Songs to connect different songsabout everyday movement of objects, such as a train, swing, bicycle, weather cycle, jump roperhyme, fishing rod and others the class might decide on. Enlist the help of the music teacher toincorporate musical instruments to demonstrate the movements of objects on different surfaces.Cooperative groups could design a mural, diorama, or three-dimensional representation of astory that illustrates a variety of movements.

Teaching Tips and Guiding Questions

Engaging questions stimulate enthusiasm, questioning and exploration that will help guide thechildren in their thinking and lead them to the big ideas.

Questions that might guide and engage children’s thinking during the investigations andconnected extensions include the following:

• Where do toys get the energy that makes them move?• Where do you get the energy to move your body?• Where will the energy come from to move these objects?• How is wind energy used in the real world to move things?• Does the same amount of energy from your blowing move the objects the same distance?

Why do you think that is so? (weight of object, shape of object, kind of surface, etc.)• Why do some objects travel farther or faster than others?• How does the surface affect how an object moves?• How does gravity affect the way your object moves?

Note: This is an example of an early brainstorming with first and second graders before startingthe exploration about rolling, sliding and bending. What objects might move in these differentways?



Slide Roll Bend

sled basketball wire

snowmobile skateboard rubber pencil

snowboard dirt bike body

skis soccor ball frog's legs

snow tube beach ball straw

Jenga game marker

pen

marbles

fingerboards

At the end, I asked the question: What do you notice about the objects you listed in eachgroup? My students concluded: “The objects under ‘slide’ are long and flat; and the objectsunder ‘roll’ are round. The objects that bend are thinner and more bendable.”

Concepts to be Assessed

(Unifying concepts/big ideas and science concepts to be assessed using the ExemplarsScience Rubric under the criterion: Science Concepts and Related Content)

Physical Science – Properties of Matter: Students observe physical properties of matter, sortaccording to similarities and differences, and identify characteristics of materials.

Physical Science – Motion and Forces: Students observe and compare physical properties ofmatter and see that an unbalanced force acting on a object changes its speed or path of motionor both.

Design Technology – Use of Tools: Students observe that tools are invented to extend theability of people (to make things, to move things, to shape materials).

Design Technology – Constraints and Advantages: Students observe that some materialsare better than others, depending on the task and characteristics of the materials.

Scientific Method: Students observe and explain reactions when variables are controlled(cause and effect).

Mathematics: Students count and use precise measurements. Students collect, organize andanalyze data appropriately.



Skills to be Developed

(Science process skills to be assessed using the Exemplars Science Rubric under the criteria:Scientific Procedures and Reasoning Strategies and Scientific Communication Using Data)

Scientific Method: Observing, predicting/hypothesizing, collecting/recording data, manipulatingtools, drawing conclusions, communicating findings and raising new questions.

Other Science Standards and Concepts Addressed

Scientific Method: Students describe, predict, investigate and explain phenomena. Studentscontrol variables.

Scientific Theory: Students look for evidence that explains why things happen and modifyexplanations when new observations are made.

Physical Science – Properties of Matter: Students describe and sort objects and materialsaccording to observations of similarities and differences of physical properties.

Physical Science – Motion and Forces: Students observe and record how forces can act andcan cause objects to be pushed or pulled, twisted, bent, blown, etc. Students see that forces(such as gravity) can act “at a distance” and can cause objects to be pushed or pulled.

Physical Science – Transfer and Transformation of Energy: Students describe forms ofenergy and the effects of forces on objects.

The Designed World: Students observe that tools extend the ability of people (to make things,to move things, to shape materials) and that manufacturing requires a series of steps and,depending on the task, careful choice of materials (based on their characteristics).

Communication: Students use verbal and nonverbal skills to express themselves effectively.

Suggested Materials

Collect a variety of simple, familiar objects found in the classroom, such as crumpled paper,chalk, crayons, markers, marbles, unifix cubes, wooden cubes, centimeter cubes, plastic chips,Legos, dice, paper clips, seashells, erasers, pencils, Popsicle sticks, playing cards, clay, foil,game pieces and other objects the children want to try. Provide each child with a plastic strawand recording sheets for each day. Two different surfaces can be created using any of these:table or desktops, rug samples, cardboard, cloth-covered desk tops, etc.



Possible Solutions

This task has two levels of assessment. The first can be seen in the first day’s recording ofdata. Teachers should check that recordings are accurate and that predictions change as testscontinue (e.g., objects that are rounder or flatter move in a particular way).

The second day’s recording should show continued use of prior knowledge from the first dayand also show understanding of scientific concepts and knowledge about how surfaces affectthe rolling and sliding of objects, as students compare how objects are affected by the surfaceof the floor or rug.

Six objects should be tested on both surfaces and the results recorded. The final writtenconclusions should reflect how the rug slowed down the motion of objects. The results couldreflect how the shape of an object will usually determine whether it will roll or slide. Somestudents may notice that a few objects move in both ways and will suggest why this happened.

Task-Specific Assessment Notes

NoviceThis student’s solution is incomplete in that the last test is not recorded. The student appears tobe guessing and changing observations without using reasoning related to the shape of theobjects or prior trials. The student counted up the Xs, to write the statement, “I saw moreobjects sliding” – evidence of using data to draw conclusions. However, some of the recordingsare inaccurate or questionable. (Did the cube and the die roll or slide?) Conclusions do notinclude evidence of understanding about the objects tested on the different surfaces. Oneconclusion is made about the shape of objects (round) and rolling.

ApprenticeThis student’s solution is complete, recordings appear to be accurate, and there is someevidence that the student is beginning to make predictions and observations based on priorknowledge, especially for the same objects tested both days. The final conclusions are basedon data collected, but they don't answer the “why” about the surfaces.

PractitionerThis student’s solution is complete, and there is evidence about the use of prior knowledge(using shape of objects) and recording data with accuracy. The student effectively used thetools and understood shape and surface to explain cause and effect. The final conclusionsabout the shape of objects for sliding and the rug being bumpy causing the objects to moveslower show scientific reasoning based on observations.

ExpertThis student’s solution is complete, and there is evidence of prior knowledge and experience inmaking predictions. Conclusions are supported by data, and observations are made about howdifferent materials moved on the desk and on the rug. Extended thinking is seen through the Q-tip that was described in the interview and recorded to show exactly what happened.



Novice



Apprentice



Practitioner



Expert



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