Barbie Bungee Jumping

I've been toying around with this activity for a few years now, but I've never had a class that I trusted enough to cooperate and do this.  This year the students are no different, however, I am co-teaching this class and there are two more eyes to help with crowd control.  

This activity was used with a 9th-grade Algebra 1 class.

The activity in a nut shell:

1) Students determine how far Barbie bungees with up to 10 rubber bands.

2) Students determine how many rubber bands are needed to have her jump from a higher height, but using their knowledge of regression equations, slope, and y-intercept.

3) Finally, students bungee their Barbies from that height.

The original idea came from Illumination from NCTM.

Here is the packet that I created for my students.

We started in the classroom and the students used up to 10 rubber bands.  A few problems that I noticed along the way.

- Students had difficulty finding average.  Yes, average.  They completely forgot about the order of operations with the calculator and would type this in:  50 + 49 + 51 / 3.  They neglected to use parenthesis or the ENTER button.

- The students assumed that it's okay to round.  No! No! No!  Not when Barbie's life depends on it.

 - The students did not double check each other's work.  One student solve the equation incorrectly and the rest of the group assumed she did it right.  

The big day - when it finally stopped raining we were able to bungee the dolls from a 14-foot height.

The results - Two of the groups did well. Their Barbie came within inches of the ground.  Three of the groups didn't have enough rubber bands for the reasons listed above.  Three of the other groups "killed" their Barbies with too many rubber bands.  I believe their mistake was in the classroom and not accurately measuring the bungee distance.

Reflections:

I will do this activity again.  Not only did it help students with concepts of linear equation, but it was a nice review of estimation, average, and rounding.

The students were more well-behaved that I thought they would be.  I believe this is because they were very interested in the activity.  This helps with one of my problems - being afraid of my students.  Not afraid for myself, but afraid of lack of cooperation.  Perhaps if I would show some trust more often, I would see more cooperation.  Maybe.

What I would do differently next time.
I will need to emphasize the importance of not rounding and the importance of measuring accurately.