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A Cranking Device to the Rescue!

Oh. My. Goodness. We had the MOST fun ever with this cranking device challenge! My test class loved being the guinea pigs for this challenge and helping decide on the rules of the task!  

The basic premise is that a team member has fallen over a drop-off and must be rescued. The remaining teammates must use what they have in their backpacks and sticks laying nearby to build a contraption that will reach the bottom of the ravine and then successfully wind up the fallen team member.

A cranking device to the rescue indeed!

STEM Challenge- students build a cranking device to rescue a small toy. The device must operate with a turning crank and lift the item from a three-foot drop.

Who are we going to rescue?

My first idea about this challenge was to give kids some basic building supplies and they would make a cranking or winding device. The fallen teammate would be a Lego man.  

Okay… I should have thought about that a little longer.

Students are designing a cranking device but it cannot operate as a fishing pole. It must have a turning crank with a handle.

The group in this photo made a fishing pole and scooped the Lego man right out of that ravine. It took them about 2.5 minutes to do this.   Now, my students are quite understanding and patient with new challenges. In fact, they LOVE to be the test class. They know when I announce that the group is testing the challenge that it will be interesting.

I am quite honest with groups when I tell them, “Oops, that didn’t work exactly like I thought it would!”

As soon as I say this we all know that we are about to STOP and talk about what is going wrong and how we can change the task rules and make it work better. When I saw that fishing pole I said. “AGHHHHH, time to talk about adding some rules to this task!” We came up with this: the device must wind up.

Students are designing a cranking device but it cannot operate as a fishing pole. It must have a turning crank with a handle.

Then we had this! The group from the above photo just laid the long pole on the tabletop and wound it up. With their fingers turning it.

Oops, that is not exactly what I was thinking.  

Think about it- this wooden dowel stick they are turning represents a tree branch.

How heavy is a log?

That is when I climbed up on a stool and retrieved this giant log. (I have no idea why I have that giant log in my room, but it came in handy.)   

I climbed down with it and handed it to the first student I came to. Whereupon, he almost dropped it! Ha! A log is maybe a little bit heavier than you expect! The log is about two and a half feet long and 8 inches in diameter.  

After letting everyone try holding the log and attempting to hold it and wind it, the kids understood that this would not be possible with a real log on a cliffside! So, we went back to make sure our rules for this task were detailed.  

The device that extends over into the ravine must be strong enough to attach a container and then be wound up. To wind it up we decided a handle would be best. This was after a discussion of what kinds of real things kids have seen that would work like this. Two things were mentioned- a fishing rod and reel and the jack system used in a car. A student said the jack his dad uses has a fold-out handle that makes it easy to turn.  

So, we got back to work!

Many hands at work in this cranking device STEM Challenge.

I love this photo. Sometimes I worry that groups of four students is just too many. Partners are sometimes the ideal number, but the cost of supplies keeps me from always using partners. However, we also discover that many hands are sometimes needed!

So, were we able to solve this dilemma and follow the rules of the task?

By far, the hardest part of this challenge was getting the log (dowel stick) to turn. Here are a few fabulous ways kids solved this.

Problem-solving during the building of a cranking device.

The team in this photo has a straw folded over the stick.

This gave it enough space to turn when the handle was cranked. And it held it in place nicely.

Problem-solving during the building of a cranking device.

In this photo you can see that the team punched holes in the straws and then threaded the stick through. Pretty clever!

I loved this challenge! We (the test class) worked so hard to refine and rework the task rules until we came up with constraints that made the task difficult, but doable. By the time I tried this with the next group all the kinks were worked out. The best part is that all week long I would see the test class kids and they would ask how it was going!

You may also like these rescue challenges:

STEM Challenge- students build a cranking device to rescue a small toy. The device must operate with a turning crank and lift the item from a three-foot drop.

Comments

  1. Carol Davis says

    I do have it written with details, hints about how it worked, materials list, and photos! Here's the link: teacherspayteachers.com/Product/STEM-Challenge-Design-a-Cranking-Device-2277777

    Thank you for your interest!