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Simple Machines challenge

Students will work in teams to design and build a Rube Goldberg-inspired machine that solves a simple challenge using everyday materials and at least one simple machine. Along the way, they’ll explore cause and effect, test their ideas, and improve their designs through creative engineering.

Elementary

simple machines, cause-and-effect

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Project Details

Theme

December | Product Design

Messy Level

2

Suggested Location

Lab

Prep & Classroom Structure

Before students arrive: Set up one materials station with cardboard, cups, string, craft sticks, wheels, tape, dominoes, balls, blocks, tubes, ramps, and other reusable building materials. Prepare one Challenge Card per group of 5 students and place each card face down at the team workspace. If possible, pre-sort a small starter bin of materials for each team so students can begin quickly, while keeping additional supplies at a shared materials table.


The session should feel like an engineering challenge, not a craft project. Machines do not need to look polished. Encourage experimentation, unusual ideas, and redesign.


Avoid showing students examples of completed Rube Goldberg machines immediately before building, since students may copy the solution rather than develop their own.


If a team's machine does not fully work by the end, they can still present it. Ask them to explain where it failed and what they would change next. That debugging process is part of the engineering objective.


For a 45–60 minute session, a good pacing guide is approximately 5 minutes introduction, 5 minutes planning, 20–25 minutes building and testing, 10 minutes final testing/debugging, and 10 minutes demonstrations and reflection.


How it works:

Instead of telling students what to build, each card gives them a problem to solve. This keeps the activity open-ended and avoids giving away the engineering solution.


Each team of 5 receives one card with this structure:


YOUR CHALLENGE

  • Solve the problem by creating a crazy machine that completes the task.


YOUR MACHINE MUST

  • Complete the challenge successfully

  • Use at least 1 of these simple machines: lever, pulley, wheel & axle, inclined plane

  • Include at least 3 connected actions

  • Start with one action from your team

  • Finish the rest of the sequence without anyone touching it

  • Be tested and improved at least once


ENGINEERING TEAM ROLES

Students can rotate or share responsibilities: Designer sketches the idea, Builder leads construction, Materials Manager gathers supplies, Tester runs trials, and Debugger/Reporter watches for problems and explains the final design.



Materials

Building Materials

  • Cardboard sheets and scrap cardboard

  • Cardboard tubes

  • Paper or plastic cups

  • Craft sticks

  • Wooden blocks or building blocks

  • Dominoes

  • Straws

  • String or yarn

  • Rubber bands

  • Pipe cleaners

  • Index cards

  • Construction paper

  • Aluminum foil

  • Paper plates


Simple Machine Materials

  • Toy wheels or bottle caps for wheel-and-axle systems

  • Wooden dowels, skewers, or pencils for axles

  • String and small spools, rings, or classroom pulleys for pulley systems

  • Craft sticks, rulers, or strips of cardboard for levers

  • Blocks, cups, or small boxes to use as lever fulcrums

  • Cardboard, foam board, or plastic tracks for inclined planes/ramps


Chain-Reaction Materials

  • Ping-pong balls

  • Pom-poms

  • Marbles or lightweight balls

  • Small toy cars

  • Dominoes

  • Wooden blocks

  • Cups

  • Tubes

  • Bells or buzzers

  • Lightweight objects to knock over

  • Small buckets or containers

  • Toy figures or small objects for delivery/rescue challenges


Assembly Supplies

  • Masking tape or painter’s tape

  • Clear tape

  • Scissors

  • Glue dots

  • Binder clips

  • Clothespins

  • Rubber bands


Planning & Testing Supplies

  • 1 Challenge Card per team

  • Pencils

  • Scratch paper or engineering-design sheets

  • Markers

  • Optional timer

  • Optional measuring tape or rulers

Project Instructions

  1. Divide students into teams of 5 and give each team one Challenge Card describing a problem their machine must solve.

  2. Teams identify the final action their machine needs to accomplish, such as moving an object, delivering an item, knocking something over, or reaching a target.

  3. Brainstorm a contraption that uses at least one simple machine such as a wheel and axle, pulley, lever, or inclined plane.

  4. Build a prototype using the available materials. The contraption should include at least 3 connected actions where one action triggers the next.

  5. Test the machine from beginning to end without touching it once it starts.

  6. If it stops, teams identify where the cause-and-effect sequence failed, make an adjustment, and test again.

  7. Teams demonstrate their final machine and briefly explain which simple machine they used, how one action caused another, and one improvement they made during testing.

Class Video


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