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## Race the Track! Jump the Gap (Lesson Four)

By Kathy Scoggin, February 23, 2009

• Elementary School

• Architecture

• Science

45-60 minutes

### Introduction

Students and their teachers are introduced to basic physics concepts and the idea of variables through use of Mattel™ Hot Wheels tracks and steel balls. Students will use the design process to explore force and motion. This series of lessons allows students and teachers to work through the design process in order to investigate physical science and experimental design concepts.  It highlights the design process as a tool allowing students to approach issues in a meaningful and productive way. This unit follows a learning cycle of Focus - Explore - Reflect - Apply.  The cycle is followed throughout the entire unit as well as within individual lessons.  It allows students to observe phenomena during their investigations which will lead them to ask questions and design systems in which to explore answers to their questions - and on to further questions.

### Objectives

Students investigate the intermarried concepts of variables and design.  The focus is on developing recognition of the variables inherent in their track systems and understanding how manipulations with variables  (i.e. design of the track system) can/will affect the trajectory of the ball. Students will:
• learn how to recognize variables in a system and investigate how manipulating the variables changes the outcome of a trial
• systematically collect and record data for later analysis
• develop an understanding of the interplay of the forces of gravity, force, and speed as it relates to landing a projectile on a specified target (when a projectile has the correct amount of energy it will land on target)
• recognize the design process as a creative challenge employing the skills of observation, research (data collection), problem solving, and sharing results and connect it to the process of setting up an investigation, manipulating variables and collecting data to achieve a specified outcome

The variables within the track system at this point are: Height of the launch (release point of ball) Width of the gap Size (weight) of ball

### Materials

Each group of students will need:
• track pieces (5 short)
• connectors (3)
• jump (launch and catch pieces)
• meter stick
• can (to be used as a target)
• large and small steel balls
Individual Students will need:
• Jump the Gap Data Sheet
Display for Whole Class:
• Frame of Reference Chart
• Design Process Poster

### Vocabulary

• design: plan something for a specific role or purpose or effect; the act of working out the form of something
• variable: anything you can change in an experiment that might affect the outcome
• controlled experiment: a form of scientific investigation in which one variable, termed the independent or control variable, is manipulated to reveal the effect on another variable, termed the dependent or responding variable, while all other variables in the system are held fixed
• speed: distance travelled per unit time
• distance: the property created by the space between two objects or points
• projectile: any object propelled through space by the exertion of a force which ceases after launch (in this case, the steel ball)
• potential energy: the mechanical energy that a body has by virtue of its position; stored energy
• kinetic energy: the mechanical energy that a body has by virtue of its motion
• friction: the resistance encountered when one body is moved in contact with another
• gravity: the force of attraction between all masses in the universe; especially the attraction of the earth's mass for bodies near its surface
• acceleration: a rate of increase of velocity
• system: a set of related objects that can be studied in isolation

### Procedures

1. Teacher Presentation and Motivation: Draw a Frame of Reference chart on large paper.  Use this “Thinking Map” ? as a tool to gather prior knowledge with your students:
• In the center circle record the topic.
• Invite the group to brainstorm what they know about design as you record their answers in the outer circle.
• Next, ask them how they know what they know – i.e. “Learned in another class”, “My mom is a designer”, “I saw a program on TV”, etc.  Record in the outer “frame”.  Discuss.
(Note: It is useful to keep this chart hanging in the room as your students progress through additional design experiences – ask them to add what they “learn”  {using a different color marker} into the outer circle.) 2. Present your students with the following investigation to help them gather additional background knowledge to enable them to successfully design a track system to solve a challenge provided in a future lesson.  Stress continued questioning and keen observing as they progress through the investigation. 3. Begin the hands-on investigation (allow 30-45 minutes for exploration): a) Introduce the concept/vocabulary variable.  (A variable is anything you can change in an experiment that might affect the outcome.) b) Assemble a demonstration track – ask the students to identify the components they recognize as variables in this track system. c) Demonstrate the two parts to the jump – the launch and the catch.  Demonstrate how to line up the launch and catch by sighting along the track. d) Demonstrate how to measure accurately the width of the gap between the launch and catch. e) Distribute and explain the Jump the Gap Data Sheet 4. Wrap-up/Class Discussion/Sharing Learning: Ask each group to analyze their data sheet and formulate a claim/evidence response based on the information they gathered.  Possible prompts:
• Compare the results from the small and large ball.
• How did the height of the release point affect the size the gap successfully jumped?
• What variable seemed to make the most difference in getting the ball to jump the gap?
• “This graph shows _____________________________________, therefore we think ________________________________.”
Share group responses and discuss similarities and differences. 5. If using the Design Journal ask students to individually respond in writing using one or more of the following prompts:
• I am curious about ________________________.
• It surprised me that ________________________.
• I wonder what would happen if_________________.
• How does __________affect __________________?
6. Introduce the Design Process Poster.  Continue the discussion by connecting the design process to the process of constructing a track system to achieve a specified result. 7. Stress that designers accept the task of tackling a challenge and then use a step-by-step process to develop their solution to the challenge. 8. Ask students to reflect on how the design process is similar to the investigative challenge they just completed. 9. Re-emphasize the big ideas in this investigation: a) Design is a process that invites us to become creative problem solvers. b) Observation and data gathering help us to become skilled creative problem solvers. c) Sharing thinking and solutions brings heightened creativity and success to the process. d) When a projectile has the correct amount of energy it will land on target. e) Variables within the track system will determine the amount of energy the projectile has. f) In a controlled experiment changing only one variable at a time allows for optimal data collection.

### Assessment

Formative assessment is embedded in the work and the group discussions.  Further assessment will occur as they work to solve track design challenges in following lessons.