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Activity: Solve a Transfer Challenge

Radioactive Golf Balls3(Activity courtesy of Techbridge).  Grade Level: 5-12. Time Required: One class period. Approximately 10 minutes preparation and 35 minutes for the activity. Techbridge activity pdf.

Radioactive Golf Balls

In this activity, students practice working collaboratively on a project that requires both ingenuity and speed. Within 20 minutes, they must figure out how to construct a device that can move a set of “radioactive” golf balls from one paper bag to another without human contact.


  • To work in teams to solve a problem
  • To work within a very tight deadline


Each group of students will need:

  • 2 brown paper lunch bags
  • 5 golf balls (placed inside one of the paper bags)
  • 4 four-inch pieces of string
  • 4 drinking straws
  • 2 skewers
  • 4 paper clips
  • 4 rubber bands
  • 5 Post-It notes
  • push pins
  • 1 pencil
  • 1-foot length of scotch tape

To test the devices, you will need:

  • a tape measure
  • a stopwatch


Preparation: Set up the classroom to provide ample working space for teams of 2-3 students. Each team will have two bags placed on the floor approximately 8 feet apart,  with their openings facing the ceiling. To ensure the bags do not move, tape both to the floor.

1. Divide the class into teams of 2-3 and distribute the  materials.

2.   Explain to students that they should imagine that the golf balls contained in bag #1 are radioactive.  The object of the activity is to move all the balls from the one paper bag to the other without touching the balls or tilting the bag.

3.  Using only the supplies provided, each group has 20 minutes to construct a device that can transport the balls, while observing the following rules:

  • The teams may alter the supplies in any way necessary;
  • The golf balls must be moved  one at a time;
  • No part of a person’s body or clothing may touch the golf balls. The balls must stay at least 3 inches away from any body part–notably the hand.
  • If anyone touches a ball or if a ball gets dropped, there is a contamination leak! A member of the team must return the contaminated ball to bag #1;
  • This is a speed competition!  The team whose device successfully completes the task in the shortest amount of time wins.

4. When the 20 minutes is up, have each group demonstrate its device. The team that moves all their balls in the shortest amount of time wins.


Hold a discussion comparing  the differences of each team’s device, including strengths, weaknesses, and creative solutions. What suggestions for improvement can the teams offer one another, as well as themselves? Be sure to point out that there is no single way to get the task done – there are many methods that will work.

Discuss whether having a time limit affected the end product. Working fast can be fun — but is it the best approach, particularly if working with radioactive materials?


If there is time and interest, spend part of another class period allowing students to incorporate the suggested improvements and once again demonstrate their results. Can the group think up ways to refine the task to make it more challenging or intriguing? Are there supplies that would help ease, or even complicate,  the task?

Have students consider issue of sensitive and dangerous materials. What kinds of  protections and precautions must engineers build into their devices, to ensure everyone’s safety?

7 Responses to “Activity: Solve a Transfer Challenge”

  1. This is a great activity! I used it in my introduction to Engineering class at Cal Poly, SLO. It is simple enough to do in a half hour, yet I used it to discuss engineering: Design-Build-Test, and the engineering design process.

    The only thing I added is that the balls have to be 3 inches away from any body part (hand). I found when I didn’t say this, they used the sticky notes to hold the ball.

    Thanks for these great activities.

  2. I did this activity today and the kids had a “ball”! Radiation leaks were plentiful, but every one had a great time and cheered each other on! What a fun team-building exercise!

  3. Thanks for the feedback; let us know if you have any additional suggestions, or engaging lessons to suggest.

  4. That’s a great tip, thank you, Lizabeth. We’ll incorporate it into the lesson.

  5. Would you have to use the push pins? Is there a safer substitue?

  6. Hi Rachel,

    It would seem that you can definitely use another type of material like glue sticks or poster putty. It might be fun to try out several types of supplies with this activity. If you do change the activity, we would love to hear all about it and how it went. Please let us know if you have any more questions.

    Thank you very much,


  7. What are the solutions for this?

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