45 – 60 minutes

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 utilize 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. See Learning Cycle attachment.

 

Science

Level II: Standard 10.Understands forces and motion 2. Knows that the Earth’s gravity pulls any object toward it without touching it  5. Knows that when a force is applied to an object, the object either speeds up, slows down, or goes in a different direction 6. Knows the relationship between the strength of a force and its effect on an object (e.g., the greater the force, the greater the change in motion; the more massive the object, the smaller the effect of a given force)   Standard 11.  Understands the nature of scientific knowledge 2.  Knows that good scientific explanations are based on evidence (observations) and scientific knowledge 4.  Knows that scientists review and ask questions about the results of other scientists’ work Standard 12.  Understands the nature of scientific inquiry 1. Knows that scientific investigations involve asking and answering a question and comparing the answer to what scientists already know about the world 3.  Plans and conducts simple investigations (e.g., formulates a testable question, plans a fair test, makes systematic observations, develops logical conclusions) 5.  Knows that scientists explanations about what happens in the world come partly from what they observe (evidence), partly from how they interpret (inference) their observations  

Students calculate the average speed of a ball as it travels the length of a track. Attach the track to tall and short objects in the classroom to change the slope. The slope of the track will affect the speed of the ball. (This lesson is a pre-activity to the upcoming design/inquiry process in which children build first-hand background knowledge of the elements of height and slope in track design and how this affect the speed of a ball.)

• Develop the notion that a variable is anything that you can change in an experiment that might affect the outcome and, in a controlled experiment, only one variable is changed, and the results are compared to a standard
• Develop students’ understanding of motion and forces
• Provide opportunity to utilize the design process to help plan and conduct an investigation
• Develop an understanding of science/design as a human endeavor in which the work of science/design relies on basic human qualities such as reasoning, insight, energy, skill, and creativity—as well as on scientific habits of mind, such as intellectual honesty, tolerance of ambiguity, skepticism, and openness to new ideas

Each group of students will need:

• Super Slope Worksheet
• track pieces (8 short)
• connectors (7)
• c-clamp
• stopwatch
• calculator
• meter stick
• roll of tape
• can
• small ball
• O-W-L chart  (2 per 8.5 x 11 master)
• journal

  Set-up: 1.  Make copies of the Super Slope worksheets. 2.  Assemble materials station. 3.  Set up a demonstration track. 4.  Put students in small groups. Teacher presentation & motivation: 1.  Use the demonstration track to show the class how to assemble track and model activity 2.  Distribute and explain the Super Slope worksheet 3.  Demonstrate how to measure the length of the track in centimeters. 4.  Demonstrate how to use the stopwatch 5.  As a class, go through the first test with the track attached to the seat of a chair: Using the stopwatch, find the time it takes for the small ball to travel the length of the track. Record the time.

• Repeat first step.
• Using the calculator average the two times recorded.
• Using the calculator, determine the speed in centimeters per second. (cm/seconds)

Step-by-Step process: 1.  In their individual groups, have the students assemble a straight track using 8 track pieces and 7 connectors 2.  Measure the length of the track in cm. Record the measurement. 3.  Attach one end of the track to a chair back using the C-clamp or tape. Place a can at the other end to stop the ball. 4.  Release the small ball from the release point. Use the stopwatch to find the time it takes to reach the can 5.  Record the first try on the data chart. Test and record the second try. 6.  Use the calculator to find the average of the first and second times. 7.  Calculate the speed of the ball at this release height. 8.  Remove the track from the chair seat and repeat steps 3-6 for the following heights:  The shoulder of a team member; an object in the classroom. Wrap-up/Class Discussion: 1.  Ask your students the following questions:

• What did you notice about how your track system worked?
• What did you observe about how the height of the release point affected the speed of the ball?
• What did you observe about how the slope of the track affected the speed of the ball?
• What can you claim about the difference in speed between the small and large balls?
• In what kind of real-life situations can you think of height or slope or speed mattering to someone?   (Prompt discussion leading to such things as amusement park rides, skateboarding parks, bicycle trails and races, water slides, etc.)

2.  Talk with the students about this lesson as the first step in a journey to discover how  people (adults and kids) use a process to help them solve problems.  This is often called the design process and is used by people like engineers, scientists, and artists.  Talk about the upcoming  series of inquiries as experiences where they will set out to solve specific problems by using what they already know (past knowledge), tinkering around and trying things, using creativity and imagination, making mistakes, and trying again. “In the next activity we’ll use what we’ve learned today about how balls travel on these tracks and make their “ride” even more exciting.”

Post discussion you may wish to use the O-W-L Charts giving students the opportunity to independently write what they Observed-Wonder-and Learned during this investigation.  

• Students can create graphs to show the results speed results of their tests.
• Students can convert cm/sec speeds to mph speeds.
• Students may keep a Design Journal (see attachment for suggestions).