Indiana Science Grade 8

Unit 3: Physical Interactions

Slow tunnels

Introduction:
In the movie Apollo 13, a crew of astronauts returning to Earth in a damaged craft seeks help from NASA flight engineers to make their oxygen system operate through the duration of their perilous mission. The team on the ground is challenged to make an oxygen filter from one system operate in a different system—to literally make a round peg fit into a square opening. The task facing the NASA team involved using a limited array of materials available to the astronauts on the space craft, such as duct tape and socks, to make the oxygen filter work. They relied on creativity, ingenuity, and teamwork to understand and successfully solve the problem.

Given the NASA team's situation as inspiration, how can a system be designed and constructed to keep a table-tennis ball in motion for a maximum amount of time using appropriate recycled materials available in the classroom?

Task:
Divide into teams and collect the following construction materials:

• 25 sheets of recycled, 8 ½ x 11 paper (collect non-confidential draft copies of paper from copy machines and printers, as appropriate)
• 5 meters of masking or duct tape
• 1 table-tennis ball
• 1 poster board

Each team may use this set of materials (with no other materials from any other sources) to design and construct a system of tubes, turns, ramps, funnels, and troughs. These features will be created from the paper and tape and will be mounted to the poster board that will rest on a flat surface (such as a large table or the floor). The system should be designed so that a table-tennis ball rolled through it will move for the maximum amount of time.

As a team, make a diagram of the system you plan to create. The diagram should include the shapes of the features that will be mounted on the poster board. Consider the size of the poster board and the connections between the features in the design. The system must be contained within the space on the poster board.

Once the design is complete, each team will be given an equal amount of construction time. After modifications have been made, time trials will be run for each team's system. One student on each team will serve as the timekeeper and the other student will run the table-tennis ball through the system. Each team conducts three time trials. Collect the three trial times and calculate the average time. Record all information on the class data collection table.

Sample Class Data Collection Table

Team	Trial 1 (s)	Trial 3 (s)	Trial 3 (s)
1
2
3
4

After all teams have conducted their time trials, answer the following questions:

1. After designing, producing, and testing my system, as well as observing other people's systems, what would I do differently if I repeated the process?
2. Select a different team from your class. Based on your experience, what suggestions would you give that team in order to increase the amount of time that their table-tennis ball stayed in motion in their system?

Time:
1 class period to create a system design , 1 class period to build the system, test it, and make modifications to it, 1 class period to conduct time trials, collect data, and answer the questions.

Possible Resources:
http://www.rube-goldberg.com/html/contest.htm - Read about Rube Goldberg machines
http://www.anl.gov/OPA/rube/rube.html - Investigate the Rube Goldberg Machine contest at the Argonne National Laboratory
http://www.mindport.org/aerotrak.html - Visit this site to learn about a table-tennis ball and tube museum exhibit