ZIP LINE DESIGN CHALLENGE: Grade 3 students rescue Ranger Bear

Students sketch design ideas while considering building materials


We’ve been thinking a lot of how to meaningfully integrate elements of the Next Generation Science Standards into our design challenges. We had done a zip line challenge a couple of years ago and although it was successful in terms of student engagement, we felt that we hadn’t really developed the potential of this activity. This year we decided to go with a hybrid. We created a scenario using a stuffed bear dressed as a National Park Ranger. We splinted his leg with a craft stick and a bloody tissue. Then we told the students that he had been up on the mountain observing birds when he tripped and injured his leg. (You may be grinning but this hype really motivates grade 3 students to invest!) We crafted a “needs statement:”

Ranger Bear NEEDS a zip line IN ORDER TO get down the mountain to the first aid station.


These were the basic steps we took:

Introduce the challenge and the Needs Statement

Research zip lines using a of YouTube videos and articles we had found

Unpack key science concepts that would impact designing: Gravity and Friction

Introduced materials for prototyping a model

Had students individually sketch potential designs

Partnered students and had them “pitch” their ideas to each other

Partners received feedback and decided on or formed a final sketch to begin building

Partners decided on final design to build

Partners decided on final design to build

Cycled through prototype-test-adjust wheel of experience

Final zip line tests and reflection


It was interesting to watch the students engage in this challenge while trying to synthesize the scientific aspects of the task with the design constraints. Most students realized that they would need to reduce the amount of friction and increase the amount of weight in order to have their device move smoothly along the zip line. Once they had met that criteria, they had to reevaluate and seek to balance the comfort of the injured bear with the need to move their rescue device quickly down the line with a sense of urgency. A lot of the initial prototypes crashed into the wall at the bottom of the slope, giving the poor bear a concussion and perhaps a fractured vertebrae. As they refined their prototypes, many students were able to craft rescue devices that supported the bear comfortably and helped him arrive at the rescue station in a timely manner. Student engagement was sky high for this challenge, beyond what we had experienced before. We have a strong hunch that this came from the empathy attribute embedded in the challenge.


We’re still working with exactly how to build science understanding within the frame of a design challenge. In order to help the students consider the impact of speed and weight on their design, we pulled these concepts out as separate attributes.

Next time, we realize that we need to develop these ideas as they specifically relate to gravitational pull and friction. Since we plan to focus on gravity and friction in future design challenges, we have an opportunity to deepen their thinking by building on prior experiences.

A last reflection we added was specifically looking at how students felt about the design process.  We asked them to rate their feeling about different design components.  Then, we asked for them to talk about a change they made and what they might try next time.  We are trying to build an understanding that improvements can always be made as we continue to think about work we have done.