1. Evan McKenna and Stephan Strok
STEM MARBLE RUN
Evan McKenna and Stephan Strok

2. The problem
How long can we keep the marble in the marble run?

3. Gravity
To understand how the marble moves we first have to understand how gravity works Gravity, or gravitation, is a natural phenomenon by which all things with mass are brought toward (or gravitate toward) one another

4. How gravity affects the marble
Now that we know that gravity is, time to start making the marble run. So if we want to accelerate the marble we need to slope the track downwards and if we want to slow it down we need to build a bump. See diagram on next page:

5. Diagram
To speed up the marble we need a downward slope, here's how it works: To slow down the marble we need to slope the track up:

6. Here is an example of gravity being used in a marble run

7. Friction
To slow down a marble we can also use friction to our advantage. Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other.

8. Example of friction
An example of friction would be if you are pushing a heavy box. It is hard for two reasons:
The box is heavy
Friction. The box is rubbing against the ground which creates friction. Usually this is bad but it can help our marble run. If you don’t want to create a bump on your run, you can use sandpaper or any other material that causes friction to slow down the marble

9. Marble Run
So now that you know what gravity and friction are and you know how to slow down and speed up a marble, you should be able to build your own marble run but we will still provide an example. Materials : kitchen roll, cereal box, duct tape and a marble (obviously!).

10. Final Diagram and example

11. Explanation of Diagram
On the previous page, we drew a diagram of a simple marble run and provided an example of a homemade, simple but effective marble run. As you can see on both marble runs, they start of with a downward slope to accelerate the marble and bumps and ramps to keep it at a reasonable speed. We also used friction (underlined part is sandpaper)to slow down the marble.

12. Conclusion
And that, ladies and gentlemen, concludes our presentation about physics and how to build a marble run! Thank you for your attention! Any questions?