Note:
This is a lesson by Dan Meyer. Check it out here.
The Goods:
- Use this…Desmos Activity
- Celebrity Age Guessing Presentation
- Desmos Table and Trend Line Template
- Padlet page for student sharing
The Lesson:
The teacher leads the students through the Celebrity Age Guessing Presentation. The students fill out the handout below throughout the activity. I made a Google presentation in order to easily change the celebrities and ages from year to year.
After the students get all of their data, they will input it into Desmos. See link below.
I included a table and a slope-intercept form equation in order for the students to find the line of best fit. Give the students some time to play with it. Then, have the students compare their equations. All of this provides a good discussion about what a trend line is and why it’s important.
Eventually, the teacher guides the students to find the “perfect guess” line. The class will use this in order to figure out who the best guesser was for the day. This also provides a good opportunity to discuss which scatterplots show the most accuracy. We can talk about why the graph on the left shows more accuracy than the graph on the right.
After having this discussion, the students will evaluate each other’s graphs and vote on which one was the most accurate.
This is where I need some help. What is the best way for the students to share?
I can think of 4 options:
- The students walk around the room and put rankings (1 to 5) on each graph.
- Use AirServer to display student screens on the projector.
- Have the students take screenshots of their graphs and upload them to a class Dropbox account. The teacher can then display the images on the projector.
- A combination of the first 3.
Update: Desmos tweeted this great idea:
@DaneEhlert Neat lesson. Have each Ss link their Desmos graph on a @Padlet page. Then add a link to a Google form for voting & total results
— Desmos.com (@Desmos) April 7, 2014
Padlet Page:
Here is the Padlet page with a Google form.
What did I miss? How can I make this better? As always, I appreciate any feedback.
When Math Happens 
I might like to do this a little later in the year when students can write an equation for their guessing thereby allowing them to predict what their guess would be based on the person’s real age. Also I would probably have the “real age be the x-coordinate?”
Thanks for the comments, Reiko. I like your idea about using it later in the year. I originally used it at the beginning to align with my district’s scope and sequence and to have a fun activity to begin the year. The students may be able to understand the point of the equation better later in the year though. Also, I just edited the handout to reflect the real age being the x-coordinate. Nice catch! Thanks for the help!
You can also use Reflector 2 to display a students screen onto a projector. This app give you more powerful features including recording and mirroring multiple devices at once, extended security options and easy-device management. You can also use it cross-platform for a BYOD environment.
Thanks for pointing me to that! It looks very intriguing. I’ll have to investigate it for future lessons.
My students loved this. Thanks for making it so easy to use. I added a picture of myself as the last slide. Luckily students were cautious and guessed on the low side for that one.
Haha thanks for the kind words! I’m glad it was useful. Thankful for Dan Meyer as usual on this one because the kids always love it!
The student handout link doesn’t work. Is there an updated link? Thanks!
Thank you for letting me know! I deleted that handout because I like the Desmos activity better. All the handout had was columns for the kids to write their guesses. Nothing fancy.
Excited to use this next week in my 8th grade class! I’m also thinking about tying in Mean Absolute Deviation. Thanks for the easy instructions !!
Thank you for the kind words! Let me know how it goes/went!