Barbie Zipline and a Rain Delay

A huge shout out to John Stevens and Andrew Stadel whose terrific blog posts made this activity possible. I highly recommend checking out their work first, if you haven't already. Also, thanks to Mrs. B-V who ran this with her Grade 8s at a different school earlier this year, then shared some feedback and a video with me since I couldn't be there to join them. Unfortunately, the Grade 7/8 class I did the Barbie zipline with was at a school that doesn't have a second floor classroom or balcony that we could access. To make the zipline more accessible than using the flagpole we scaled it down a bit and decided to give the students a choice between using the top of a backstop, or swing set as their launch point.

The Setup:

Following John's lead we tried to set the hook by introducing the activity with a zipline video from Nepal. It didn't get the "OOOHH"s and "AAHHHH"s that we were aiming for, but the kids were engaged, and more importantly it sparked curiousity and conversation about ziplining and what would make it fun. Click here for the presentation file we used. After a quick overview of the handout, we headed outside armed with clipboards, pens, a few fiberglass measuring tapes and a goal of designing:
1. A zipline that would be instant (certain) death for Barbie.

2. A zipline where Barbie might get stuck or lack the thrilling experience.

3. A zipline that’s just right so Barbie goes from point A to B at a safe (but fun!) speed.

Here we gave students the choice of where they wanted to setup their zipline.

Me: "How high do you think the swings are? (Crickets) No really, make a prediction. How far do you think it is from the bar to the ground?"

Students: "10 feet?" "18 feet?" "Nah, that's too high." "15 feet." "3 meters." "5 meters." "Hey this is like Estimation180!" "We haven't done that in a long time."

Me: (heart sinks)

Students: "4 meters." "More like 3.5 meters." "12 feet, it's like double your height."

Me: (smiling) Lets find out!

The swing set came in at 10' 9" and the backstop was an even 12'. We did measure in meters as well, but none of the groups chose to use the metric system.

Part #1:

Once they knew the heights they were off measuring, with their partners, how far away the zipline should run for it to be boring, fun, or disastrous for Barbie. Going purely on intuition most of the students had a pretty good idea of what would and wouldn't work. When it came time to calculate the length of the cable needed for the zipline, those that knew the Pythagorean theorem were good to go, and those that didn't were given support as needed. As for calculating the costs, we decided to drop the budget restriction and scaled back the cable costs in an attempt to address a couple of the bugs Andrew had mentioned. It was a beautiful day to be working outside!

Homework:

Students: bring in a barbie doll or other action figure

Me: pick up the equipment needed and enough "cable" for each groups ideal zipline.

I went with mason's line for the zipline, 3/4" pulley, carabiner to connect the zipline to the launch point, conference lanyard for a harness, duct tape to dress Barbie and strap her into the harness, GoPro Hero2 to record each run, one-wrap velcro to strap the GoPro onto Barbie, and a binder clip to use as a release.

Part #2

Before we went outside to do the trials, everyone got their Barbie/figure/stuffy harnessed up, measured and cut the length of line needed, and tied a loop at each end for the carabiner to hook onto and to hold at the end of the run. We went with 2 pulleys and 2 carabiners so that as the first group was getting hooked up, the next group was getting their line ready in an effort to keep things moving. Luckily, we hit some poor weather last week, and were forced to delay the the trials until Friday. The reason why it was good luck, is because I caught this conversation Thursday on Twitter.

This got me thinking...how would we decide which ziplines were really fun? Hello emoji rating sheet! As each pair tested their zipline, everyone rated the ride on a scale of sleep (stuck on the zipline) to medic (crashed hard). Although it's still subjective, it worked for us.

The Results:

Everyone got involved, and we had fun! After each group tested their zipline we returned to class to consolidate and assess which length made for the best possible run. As a whole group we discussed which emoji represented a great run, but we had a 2-1 split between excited and scared. To determine the score for each zipline we totaled the number of votes they received that fell into either of those categories. To wrap up and extend their thinking we left them with the following next steps:
1. What if we wanted to launch Barbie from the 110’ communication tower, how long should we make the zipline to be safe, yet fun?
2. How far away from the base of the tower would we have to anchor the end of the zipline?
3. Design a method to get barbie back to the top of the tower without someone having to climb back up.
4. Design a braking or stopping method that we could use for the tower run.
One of the students has volunteered to compile and edit the footage to make a video which I'll add to this post when he is finished. Until then, here is a clip from one of our runs.
*Update: Video of all the ziplines posted here on YouTube

Now if only I can convince admin that we need to test the student designs from up here on the communication tower.