Marbleslides Is Here

Marbleslides is the latest activity from my team at Desmos. It’s simple. We set up some stars. You press a “launch” button and marbles drop.

But here you have collected zero stars. No success.


That’s because your students need to set up parabolic, linear, exponential, sinusoidal, or rational functions to send the marbles on a trip through those stars.



That’s Marbleslides and you and your students should play it this week and let us all know how it goes. If you want a preview, head to LINK and type “eht8”.

If you want to set up your own class, head to the Marbleslides activities listing, choose a function family, and get a classcode of your own.

Here are some quick, below-the-fold notes about what we’re trying to do here and why we’re trying to do it.

Delight. Whenever possible we want students to experience the same sense of delight about math that all of us at Desmos feel. Students can experience that delight both in pure and applied contexts and Marbleslides is that latter experience. Seriously, try not to grin.

Purposeful Practice. Picture two students, both graphing dozens of rational functions. One finds the experience dreary and the other finds it purposeful. The difference is the wrapper around that graphing task. If the wrapper is no more purposeful than a worksheet of graphing tasks, your student may fatigue after the first few graphs. In our Marbleslides classroom tests, we watched students transform the same function dozens of times – stretching it, shrinking it, nudging it up, down, left, and right by tiny amounts. That’s the Marbleslides wrapper. Students have a goal. Their pursuit of that goal will put you in a position to have some interesting conversations about these functions and their transformations.

BTW. Here’s the announcement post on the Desblog.

Tagged in:
I'm Dan and this is my blog. I'm a former high school math teacher and current head of teaching at Desmos. More here.


  1. I did marble slides with exponentials in my class. They had to graph exponentials by hand the night before for homework and struggled, so I thought it would be a great opener for the class. The kids loved it. Great set up in low entry point and working its way up to attainable challenge problem. Love the SUCCESS feedback on each slide. When kids first try to change the base, they use 2, 3, 4, 5. They have to realize it might be something other than just an integer. I had a tech problem with it yesterday morning, tweeted at Desmos, they were right on it to fix it and let me know it was fixed. They even said they were on standby for me. This support was awesome. Thanks, Dan, for following up after to check in and see how it went. I think it really solidified their understanding in a fun way.

  2. Hi, cool activity. My only concern is with pedagogy–I would like to use this as an activity to ensure my students can use transformations of quadratics effectively. It would have been nice to have more “Fix It” type pages without a restricted domain, where students would model a curve of stars with a parabola. By introducing the ramp mechanic almost right away, I think students will just start guessing the transformations without thinking about their meaning. I would have liked a few more Fit-It problems where students could explore one or perhaps two transformations. Once through those, I would have liked a few more with three transformations and then introduce restricted domain.
    Best wishes.

  3. @JP, thanks for the concern. Our near-term goal is to release Marbleslides as an authoring tool for teachers. At that point, it’ll be great to see what you come up with!

  4. I agree with JP…love the concept, but I need way more practice for my students (who are primarily in special ed) with the general curves without the restricted domain before I throw that in the mix. Would love to see that authoring tool when it’s ready!

    I have to say, though, Desmos has been pretty accommodating. I emailed them over the summer regarding increasing the timeout on the Polygraph game which was WAY too low for my kids with slow processing speed (it was down around 15 seconds or something), and they seem to have fixed it.

  5. I’m so pleased!

    I’ve been using an ancient program called Green Globs for years, which is conceptually similar, and generates lots of student engagement.

    I’ve been wondering what would happen when all of the Windows XP computers were replaced by Chromebooks. (No more Green Globs…)

    It looks as if Marbleslides will fill some of the gap.

    I hope that the developers at Team Desmos will have a look at Green Globs. They should also read a book called “Steal like an Artist.”

  6. Ernest, I had the same thought this morning. Green Globs is fantastic. I have used Desmos to play a simplified version where I just placed and labeled points on the plane and had students create functions to go through the points, but some of the magic was missing.

    I would love to see a Desmos version of Green Globs.

  7. @Scott and @Ernest, there was a period of time earlier this year where we were simultaneously a) developing Marbleslides, and b) discussing a partnership with the Green Globs creators. All throughout that time, the connection between the two never occurred to us.

    In any case, we love the spot in edtech history Green Globs occupies and would love to do anything we can to see that the next generation of math students gets to play with it.

  8. Just a quick thanks. This activity is fun as a game, full stop. I think a key factor is that the animation of the marble physics is so well done. Of course, nice that it has value for teaching math.

    I couldn’t resist making a bumpy slide out of a sine + linear terms and playing to get the marbles to smoothly glide down the graph.

    BTW, I noticed the parabolas activity cautions teachers to look out for students using line segments. Aren’t lines just degenerate parabolas?

  9. Thanks so much for this great math activity. The fun-factor is very high, I think largely because of the realistic marble movement. I used the lines version in Algebra 1, and the parabolas version in Algebra 2, and enjoyed watching highly engaged students who didn’t want to stop when the bell rang. Later in the day the dashboard indicated they were still playing, although they had moved on to other classes.

    I will look forward to the editable version!

    The number one request from students was a way to create their own challenges, by placing the stars and perhaps adding some “barriers.” Keep up the great work.

  10. My Pre-Calc students played the polynomial version on Chromebooks and loved it. The best part for me is that they’ve now moved from “let me check my notes” when solving problems and sketching curves, to having these come to mind very quickly after a ton of worthwhile practice. Thanks for putting this together! I plan to use it again as we get deeper into graphing exponentials and periodic functions.

  11. I keep running into inadvertent physics lessons that are blowing my mind.

    It seems like there’s a touch of randomness to the individual marbles — designs that depend on marbles flying through the air show the marbles taking slightly different paths, in the same launch and across different launches. Is there any special magic or thoughts you’d like to share behind that apparent randomness? Is it intentional, or a happy accident? Did you find any other fun quirks while putting this together?

  12. @Dave, I’m part of the team at Desmos and can help answer some of those questions. The randomness in the marbles is there partially to make it more interesting / delightful to watch, and partially to encourage students to work on solutions which work for a range of inputs, instead of adjusting little details by tiny amounts until you get the perfect lucky bounce.

    It’s also helpful from an implementation perspective because getting exactly the same behavior every time would require absolutely everything about the simulation to be completely locked down. If we tried to reproduce the trajectories exactly, then any kind of tiny change in how we sample the graphs, or in how the computer computes trig functions, or what resolution we run the simulation at would break the results, but with this approach the balls will still be drawn from a similar distribution of trajectories.

  13. I have been waiting 20 years for either a Green Globs update or an alternative that is its equal. I have high expectations and cannot wait to play. Thanks.

  14. About to try Marbleslides today with my class. I agree that I’d love to be able to author my own Fix its. I also tried something that sounds similar to Green globs on my own. I gave my Alg I kids some points to aim for and told them to just create lines that go through the points. To work on Domain you could also have points you want to hit and points or walls or other things blocking you that you cannot hit, hoops to jump through. The possibilities seem endless.

  15. Marie-Hélène Simard

    November 25, 2016 - 12:17 pm -

    This is such a great activity!!! Some students have created crazy and original slides so remarkable that I would like to put them as an hyperlink for others to see. How can we do that?