- Stuff to build the marble run with: cereal boxes, paper towel or toilet paper tubes, paper cups, and so on. Try to use all recyclable materials.
- duct or masking tape
- raised surfaces (such as a wall, shelf, table, and/or chair) to build the marble run against
- a stopwatch or timer
We challenge you to design a marble run that makes a marble move as slowly as possible.
There are 3 constraints for this challenge (an engineering constraint is a limitation on your design):
- The marble has to keep moving through the entire run.
- The run needs to change directions at least 3 times.
- It must take a minimum of 10 seconds for the marble to travel the whole track.
- Friction—a force that slows things down when they rub against each other.
- Gravity—a force of attraction that pulls everything toward the center of the Earth.
- Drag—a force that happens as things move through air or water, which causes friction.
- Momentum—a force that makes things keep moving once they’ve begun.
- How can you increase friction to slow the marble’s momentum?
- If a steep incline makes a marble pick up speed, what happens if the slope is barely noticeable?
- What kinds of surfaces might cause drag and slow the marble down?
- Experiment with the materials you’ve collected. How can different lengths of track affect a marble’s speed?
- How does changing the marble’s direction impact its speed? Remember—you need to do this at least 3 times in your run.
- You’ll need to figure out what you will build your marble run on, such as pieces of furniture, a wall, a big piece of cardboard or poster board. Whatever you decide, make sure you get permission before you start.
- Put your marble run together by using the design you sketched.
- You might want to build out a few pieces at a time so you can adjust as you go. As every engineer knows, what looks great on paper doesn’t always work out once you’ve started actually building!
- Set your timer for 10 seconds. Your goal is to make the marble take at least that long to roll through the run.
- Put your marble through the run. Watch carefully: where does it speed up? Where does it slow down? Does it pause anywhere, like at a point where it drops to head in a new direction?
- Did your first design work as planned? Engineers hope for that result but know that it rarely happens. There is almost always something that can be redesigned to work better.
- Did your marble stop before it reached the end of the run? How can you adjust the design to keep it rolling?
- Did your marble speed up too much through a particular section? What if you put some kind of material along the bottom of the track that creates friction and slows the marble down?
- Would adding speed bumps help to slow the marble down anywhere?
- See if you can make the marble move even more slowly through the run.
- If this design challenge was easy, ramp it up. Can you make a longer run and keep the marble moving slowly? What about building a marble run that sets off a domino run or other chain reaction?
- You can email photos to DiscoverE at social@DiscoverE.org
As you work through possible designs, think about what you know about:
Test Your Marble Run
Evaluate and Redesign
Make Change and Try Again!
Share Your Results with a Teacher, Parent/Guardian, or DiscoverE!