This STEM Challenge turned out to be fun and so packed-full of learning.
My students were a little skeptical when I started talking about this challenge.
Turns out- they loved it! (I think their skepticism was in not understanding what we were building!)
And then they learned so much. That’s a win-win for me (and for them). So, as always, let me share a few things- especially four things to absolutely avoid when you try this.
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I learned a lot too! And I have tips for you!
I am almost always guilty of trying things and I have no idea what’s going to happen. Now, I don’t mean things like jumping out of an airplane (although I have done that)- just the small things in the STEM Lab. I invent the challenges and we try them.
Sometimes this works great and other times I learn what not to do. So, let me help you! (That is, after all, what this blog is for!) Let’s get going with these four tips:
- Pre-teach. Pre-teach. Pre-teach.
- Stuff the plastic hands first.
- Tying knots is hard.
- Allow enough time!
My students were rightfully confused about this Robotic Hand challenge. Here’s how I solved that!
I gave them these instructions:
- Hold your hand out in front of you with your palm facing outward.
- Use the other hand and lightly place a fingertip on the first tendon- below your pointer finger.
- Now, curl your pointer finger. (They should be able to feel and see the movement of the tendon.)
- Now, keep your hand in front of you and place your fingertips on the muscle in your forearm.
- Curl all of your fingers into a fist. (They should be able to feel the muscle movement and see the tendons move in their hand.)
- We had a major AHA moment over this simple demonstration. Then we looked at a few images of robotic hands.
In the photo above look at the hand that is all blue. On the fingers of that hand, the straws represent the finger areas and the tendons that lead from the hand to the bones of those fingers. The lower straws represent the tendons of the hand – the tendons students could see moving when they curled their fingers. By pulling the strings the fingers lift.
TIP: Don’t introduce this Robotic Hand Challenge expecting students to jump right in. Pre-teach by a demonstration and some online photos. (I found mine by just googling robotic hands.)
Stuff the Hands First
We used two different methods for creating our hands. Students could choose a plastic glove or make a hand from cardboard. We learned the hard way that adding the stuffing to the plastic hand after taping on the straws was the wrong way to do this!
In the photo, there are two things to avoid! First, the team taped the straws in place and then later tried to get the stuffing inside. We found that the straws came loose a lot as the stuffing was added which just meant a lot of repairs.
Secondly, in that photo, you might notice that the straws are whole. The team wanted to use the bendy part of the straw as the joint movement in the fingers. All other teams cut straws into pieces to represent the sections of each finger. So, did this technique work? Yes, the fingers actually did lift! However, they did not go back down when the string was released. The team had to move the fingers back into place. It was a great learning experience.
TIP: Save the stuffing for last and it really does work better to cut the straws into pieces.
Tying Knots is Hard
Oh, boy, I knew this already, but had forgotten it! Students know how to tie their shoes, but when you tell them to tie a knot they often do not know what you mean.
What I mean is double-tie the string so it forms a hard knot that won’t come loose.
Let me explain. We needed to tie the string to the ends of each finger. You can see this more easily on the cardboard hands.
We punched a hole in the ends of the fingers with a hole punch. To attach the string- thread the string through the hole and then tie it back to the string around the end of the finger. Tie it again and you have a knot that will not come undone.
But, students skipped the step of wrapping the string over the top of the finger. They wanted to tie a big knot on the back side of the hole and hoped it would not pop through the hole. Except it did. AVOID
TIP: You might want to avoid tying knots. Just have them tape the end of the string.
Allow Enough Time
This one is a valuable lesson. To really go over the way the hand works and look at images and then complete the model of the hand will take a full class period.
My 5th graders could finish this in one class session, but younger students may need more than one.
For the 4th graders, we stored the partially finished hands until the following week.
Count on this taking at least an hour! In the end, you will have fabulous robotic hand models and the students will have learned a handful of new things!
TIP: Plan ahead and make sure you have enough time. Don’t be afraid to stop and store the partial hands until another day!
Can you see how full of problem-solving this challenge is? We loved it and I know your students will, too!
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