Billy started with 14 marshmallows in his mouth before the minute began and then ate 8 marshmallows every 10 seconds. Claudia started without any marshmallows in her mouth and ate 3 more every 4 seconds. Who will eat the most in the group over the course of ONE minute? What if we uncapped the minute and went forever?
I made an activity called the MarshmallowMinute that had students working in groups to eat a given number of marshmallows every so many seconds for ONE minute. I wanted them to absorb the concept of rate of change, with more than their eyes.
The MarshmallowMinute was initially designed for students in my Intermediate Algebra class, which is a lighter form of Algebra 2. Really, this activity is a first year algebra activity that can extend deeper depending on the course.
This activity provided context, fun, eating, yelling, and a jumping off place to go from graphing linear models to linear systems. It also gave another opportunity to discuss domain and range, as well as discrete (LiteBrite) vs. continuous (Etch-a-Sketch) graphs. 
Beware: one student did not understand he was supposed to EAT the marshmallows. At the end of his minute, he found a home for them in the trashcan. Poor kid.
Frustration alert! Finding fresh marshmallows that don’t stick together is more difficult than one might think. I’d actually consider making it the “Skittles Sixty Seconds” or “Popcorn Pandemonium” on my next go around.
Altering the Course 
GREAT IDEA using the Lite Brite and Etch-a-Sketch to differentiate discrete and continuous!! I am inspired to make a poster with those pics for my classroom!!
Thanks for posting this lesson! I have a question about some of the scenario cards. Some of them say “Start with… ” Does this mean that the students eat that number of marshmallows before the timer or does it mean that they just have that many in their hand and start eating from what’s in their hand? I hope my question makes sense.
Thanks in advance!
That’s how many marshmallows they have in their mouth when the time starts, meaning the y-intercept differs by scenario.
Thanks for the clarification!
I am so glad I found this before I start rate of change! My 8th graders will love it.
Do you have an example of a filled out data table? I’m a little confused as to why there are so many rows. Could be a dumb question but want to make sure I do this right. I want to try it with my 7th graders.
Thanks,
Shannon
Check your email, Shannon. Thanks for the question.
Did data collection with skittles today. The kids had fun but their jaws hurt after 10 seconds or so and they moved to sorting them on their desk for the intervals of time (which I was okay with). Two kids even went to the nurse feeling sick after my class 😦 (they were warned). Anyway, in case anyone cares, I used two 2 pound bags of skittles and it wasn’t enough for two classes with 38 in each class. So buy 3 bags. It might work well with M&M’s too. I modified the activity to fit 7th grade standards and will blog about it when I’m done. This is such a great activity, I’m glad I stumbled upon it!
Thanks for the update, Shannon. I like your flexibility with the activity. I think if I run it again, I’ll explicitly give students the choice of eating or not. and see what happens. Maybe the excess M&Ms or Skittles can turn into some other activity they concoct.
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Please share an example of a completed data table with me also, am having the same problem envisioning the completed table. Also am hoping to use this with my 7th grade class!
Hi Kris,
I modified the activity to fit my 7th grade class. I typed up the lesson which includes anticipated questions on my blog at andrewsmathspace.wordpress.org called skittles in 60 seconds. It’s not perfect but definitely something you could use. I used Johns idea as the model. I would be interested in hearing how it goes!
Shannon
@andrewsshannon2