Marbleslides Madness!

Watch some students play our new Marbleslides activity.

In the first example, Maggie and Claire exemplify basically all of the mathematical practices and then some as they try and fail and try and succeed to set up their marbleslides.

In the second example, Mr. Bondley recorded his students’ free play levels, some of which were quite elaborate.


As I mentioned on Twitter, I don’t want to overstate the matter, but I think we’re seeing a level of human creativity unknown since the time of da Vinci.

Start your own class!

2016 Jan 19. One Marbleslide, Five Function Families.

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


  1. Steve Leinwand

    January 9, 2016 - 5:26 pm -

    Da Vinci may be a tad hyperbolic, but this is simply awesome. Maggie and Claire show us the engagement and productive struggle we used to only dream about. It’s like the old (very old) Green Globs on steroids raised to the 3rd power. Congratulations on a real winner and potential game changer for millions of kids.

  2. Top scores for creativity and great to see students at work. I do however, there are some impirtant things to consider with marbeslides. They primarily concern whether a goal like transformations really is covered by the current tool. Carefully designed sequences of tasks might help here (and the embedding and context of the lesson is not guven, of course), but there remain some inherently tricky things. From the video, for example:
    * The first attempt (2x+6 I think) comes out of the blue, the students then adjust the m. No attempt to first think. Further in marbleslides it does not matter what the slope is just as long as the line slopes downward. Gravity will ensure the marbles get on the line.
    * We just change the sign?
    * We just make the line a little bit longer? Is that what you want when it involves a ‘restricted domain’?
    * What’s that vertical line about (it then became not vertical but as it was just there to stop the marbles it didn’t really matter.)
    * The trial and error at the end by reducing numbers, just to make one marble go the right.

    I think the lack of precision (goal is to get the star, not to go through points), trial and error with numbers and signs, teaches limited maths. The goal is not to get the correct functions but to collect stars. I think it would be good to more explicitly link it to maths content.

  3. @Christian

    You raise some great points. I agree that I would like the students to be more precise and better understand the mathematics behind their delightful play. However, I’m curious if you think asking the teacher a few questions might be helpful here in finding out more about the journey of Maggie and Claire.

    For example,
    -Where in the learning journey are these students?
    -Will the teacher use these videos to reflect with the class as a whole so they can help each other with strategies and mathematical language/understanding?
    -Was this the first attempt by these two girls?
    -Has the teacher had a chance to view the students’ videos? If so, what’s the next step by the teacher to formalize their thinking and connect it to the mathematics?
    -Will the teacher give these two girls a chance to redo this screen by explaining the math in more detail and with better understanding/precision?

    I think this video provides a glimpse for us all to enjoy. I don’t believe it is fair to judge the lack of mathematical precision and/or understanding of these two girls if we don’t know where they are in their journey. If anything, I would praise these two girls for their positive attitude, perseverance and risk-taking without getting frustrated. I would showcase the tenacity the displayed in successfully passing this screen and ask them to use this same tenacity by refining their strategy and explaining the mathematics behind it.

    I think this video is a beautifully optimistic beginning in their journey to “explicitly link it to maths content.”

  4. Your Three Step Activities are really helpful with some activities because it gives students a bit more guidance throughout the entire problem.

    I really enjoyed this activity because you had some amazing engagement with this activity. There was so much creativity that took place with this activity. That is what I am trying to do with polynomials so it would be really interesting to have a project/problem that they have to do similar related to higher degree polynomial.

    Thank you for more great ideas!

  5. @Andrew you’re right in saying that it very much depends on how the teacher deals with this. In this case I just went with Desmos’ aims on the website, their set of tasks but also some characteristics of the tool. The goals of the activity (lines in this case) are:

    Students will be able to:
    * Restrict, reposition, and rotate lines at will using slope-intercept form
    * Use precision in describing these transformations using words and/or symbols

    So, yes, although I agree such tasks cannot be seen ‘disconnected’ from the teacher, to me there seem to be some properties of the tool that are just not very helpful. Mind you, it therefore is more about the tool rather than the teacher. What I’m afraid of is that although the tool inspires a lot of things, it also might strengthen certain misconceptions about functions. I’m sure any teacher will make sure those are overcome but why have them in the first place?

    I repeat again that I don’t doubt the inspiration students and teachers are getting from the tool but it would be good to also discuss the connection with the curriculum.

  6. Great fun. Reminds me of the game Enigmo. And I can see it creating “need” if they get tired of trial and error and want to use the laws of physics to *predict* the needed function, at which point math comes to the rescue. But it would be some hairy math.

    Interestingly, there is no “real world” relevance unless they play billiards. That’s OK, I think the real world is over-rated.

    One concern: how did other students do on this activity? Were Maggie and Claire typical?

  7. Manel Martín

    January 13, 2016 - 9:51 am -

    Hey! I’ve seen that a lot of people is creating their own marbleslines and I’d like to know how it works. I’ve tried the Free Play mode but I press “Launch” and nothing happes because I don’t have any source of purple orbs, how can I put one on the Graph? Thank you!!

  8. Kenneth Tilton:

    Great fun. Reminds me of the game Enigmo.

    Like that reference.

    One concern: how did other students do on this activity? Were Maggie and Claire typical?

    Probably not. Any two students probably aren’t typical of anybody. We field-tested this in a low-SES charter school where kids did well. Some persevered more than others. Some persevered like Maggie & Claire. Others persevered much less. We felt happy enough with the results to release the lesson.

    Manel Martin

    Hey! I’ve seen that a lot of people is creating their own marbleslines and I’d like to know how it works. I’ve tried the Free Play mode but I press “Launch” and nothing happes because I don’t have any source of purple orbs, how can I put one on the Graph? Thank you!!

    I’m sorry for the confusion, Manel. When you hit “launch” on Free Play, the marbles should fall fast from approximately (1, 500). Don’t blink!