## From Cool to Helpful, #1: The Plinko Applet

So I have been reading some of  Dan Meyer‘s  series of “What can you do with this”   posts.  Cool Stuff, to be sure.

My efforts will be less ambitious, but still helpful, I hope.  If you don’t live under a rock, you know that there are a boatload of Java Applets and interactive tools out there on the web.  I don’t even want to list a small fraction of them, because I’m sure we each have our own folder of go-to applets.

So many of these are “cool.”   But the “cool”  eventually has to become a useful too to help my students learn.  And that’s where I come in.  I know that many folks have learning worksheets around these tools, and some are really great.  Many, however,  barely scratch the surface of what will actually work in a classroom.  I think that the design & sequencing of questions / tasks / set-ups  is some of the harder work I try to do.  Sometimes I have success, sometimes I don’t.

So I want to propose an invitation to “think and play:”
1.  I post an applet that I think is “cool”  for some math reason.
2. We all play with it, and THEN
3.  We put our teacher hat on and start doing some real thinking…  Specifically:

a. What questions  would you design for  your KIDS that motivate the need to use this tool?
b. When playing with this tool, what would you want kids to see , discover, or struggle with?
c. What mathematical / practice goals  would you want your kids to leave with after playing with the activity?

So Here’s the first “cool tool” I like:   It’s a Plinko Probability Applet.   It comes from the PhET project at the Uniersity of Colorado at Boulder.   This one is particularly cool for a number of reasons.  When you change probability of a ball  falling to the right,  the little pegs actually “tilt”  to the right.

Brainstorm of the quick math topics: binomial probabilities,  empirical probability converging to theoretical probability,  impact of  n and p on the  shape, center, and variability of the distribution of pegs,  yada yada yada.  That’s the easy part.

What would we design for kids?   What questions start to emerge when YOU start playing with it?  How can this get leveraged into cool stuff for kids?    What’s the important math in this?

My intentions is to “wring out”  all of the potential in using this tool.   Maybe an effective lesson or few can emerge from this.   Let’s find out.

## About roughlynormal

I have been a math/statistics teacher for 25 years. I currently teach at an independent school in southern California. I also coach teaching fellows for Math for America - Los Angeles chapter. I love my career, my colleagues, and my friends & family.
This entry was posted in Uncategorized and tagged , , , . Bookmark the permalink.

### 6 Responses to From Cool to Helpful, #1: The Plinko Applet

1. Kate Nowak says:

I need to think more about your questions, but wanted to add this similar applet to the thread that I like a little better: http://www.math.psu.edu/dlittle/java/probability/plinko/index.html

I prefer it because it doesn’t give a preview of the histogram at the bottom. But I do like how the pegs in yours tilt.

• Kevin says:

I’ve thought about it a bit and posted a response over here. I’m not just looking for more traffic to my blog, just didn’t want my comment to be longer than your post!

2. Still thinking about your original questions. I had a response mostly written when I changed my mind. A few thoughts: I wish the histogram would display the total for each bar (maybe a mouse over feature). Without that information, we’re only really left with a shape. One way I thought about using the applet was to have students wait and watch for the first ball to say, fall in the slot all the way to the right. In continuous mode, they could pause the simulation and see the number of n before this extreme value happened. This would give a rough estimate of the probability, and could [should] be repeated. I love the animation, and the tilting, but would like to see an applet that is more “numerical”. Will have to check out Kate’s suggestion.

3. Sieling says:

I teach junior high math. Besides the probability stuff, I am betting the first question the junior highers would want to know is how fast the balls are falling in “continous” mode. It could also be a nice rate review problem. Maybe could even estimate the time to fill up your classroom if the Plinko ball was so big. Just some junior high thoughts…