4. Paper Towel Roll Marble Run (Upcycled Engineering)
What you need: Paper towel rolls, toilet paper rolls, small pieces of cardboard, tape (or reusable sticky putty), and marbles or small balls
Have students design and build a marble run using cardboard tubes on a wall, door, or inside a box. Test, tweak, and rebuild the marble run to see how changes affect the marble’s speed and path.
What they’re learning: Gravity, speed, friction, problem-solving, and basic engineering
Eco-friendly swap: Reuse paper towels and toilet paper rolls, scrap cardboard, and old boxes destined for the recycling bin.
How to adapt for lower elementary students:
Provide pre-built pieces so students focus on the marble moves.
Limit materials to keep designs simple.
Use larger balls for easier handling.
How to adapt for upper elementary students:
Add a design challenge (slow it down, add turns, hit a target).
Have students sketch their vision first.
Time and compare runs
Teacher bonus: Quieter than rockets, highly engaging, easy to differentiate for all ages, and a great excuse to raid the recycling bin.