STEM MAKER CHALLENGE
“PING PONG BALL MACHINE”
Technical Guidelines & Competition Rules 

Challenge Objective: Teams design and build a cardboard machine that keeps a ping-pong ball moving from start to finish for as long as possible. Students apply ideas about slope, friction, momentum and energy transfer, and improve their design through testing.

A teacher registers teams of 2 or 3 students in one of two categories:

• Category 1 (Grades 4-5-6): Gravity only. The ball moves by gravity alone. Motors and batteries are NOT allowed. Moving parts are welcome if they are powered by the ball or by gravity, such as seesaws, flaps, trapdoors or dominoes.
• Category 2 (Grades 7-8-9): Gravity and motors. The machine must use gravity and must include at least one battery-powered motor, for example to lift the ball, turn a wheel, or move a part of the track. 
  

Design constraints:

• The ball is released from the start position without being pushed or thrown.
• No one may touch the ball or the machine once the ball has been released.
• No coding, microcontrollers or electronic controllers are allowed.
• The machine must be built mainly from cardboard and paper. Small amounts of tape, string, straws and rubber bands are allowed.
• Ready-made marble-run kits, LEGO and other building kits are not allowed.
• The machine’s footprint must not exceed 100 cm × 100 cm. There is no minimum size or maximum height. The machine must remain stable throughout testing.
• Run time is measured from the moment the ball is released until it reaches the finish.
• The students must design and build the machine themselves. (Adults may help only with safety, such as supervising the use of hot glue or craft knives.) 
  

How Your Ball Run Will Be Judged

Your project will be scored in five areas, each worth up to 5 points, for a total of 25.  

• Documentation The team must prepare and upload three separate documents for its project in the clearest and most understandable way possible. The content and presentation style of these documents will be part of the evaluation criteria.
• Functionality Your machine should keep the ball moving smoothly from start to finish for as long as possible. Record three complete test runs to demonstrate that it works consistently, aiming for the ball to reach the finish successfully in all three.
• Creativity rewards your own original ideas, so surprise us and give your run a theme or story.
• Design checks how well you planned and built it: make the run strong and neat, and show how you improved it after testing.
• Complexity counts how many different features your run has, such as turns, drops, funnels, spirals, tunnels, split paths, jumps and moving parts. Each type counts once, and it must work in your video. 
  

Remember: the ball must start without a push, and no one may touch it during a run.

Materials: 

• Cardboard of any kind (boxes, tubes, card)
• Ping-pong balls
• Glue stick or hot glue
• Tape, string, straws, rubber bands (small amounts)
• Category 2 only: DC motors, switch, battery holder and batteries (max 9 V)
• Tools: Scissors or a craft knife, a ruler, and a timer or stopwatch (a phone timer app is fine). 
  

Safety: Hot glue guns and craft knives must be used with adult supervision.

Key Dates 

• Registration opens: 13 October 2026
• Submission deadline: 21 December 2026, 23:59 CET 
  

Required Project Forms

Once registration opens, the forms required for your STEM MAKER Challenge project will be available through the STEM Student and Teacher Dashboards.

• Project Application & Objective
• Project Development & Progress Report
• Final Project Report (Video)