If you enjoy this project, then I encourage you to buy my book, Rubber Band Engineer. It's full of more awesome and original projects crafted from household hardware. You can find it wherever books are sold.

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Students will make a simple mechanical hand with a trigger connected to a hinge. Once complete, students can test the ability of their hand by trying to pick up as many straws as possible. Extra class time (and there should be plenty!) can be devoted to further testing and redesigning to make the best mechanical hand possible!

Step 1: Materials

For this design, you will need:
(and extra for redesigning)

15 Craft sticks
Craft cubes
Round cube beads
Part of 1 Straw
2 Skewers
2 Rubberbands
Hot glue

And a box of straws for the challenge!
<p>What size craft cube would you recommend?</p>
<p>1/2&quot; cubes are used in this example</p>
<p>I helped my 7-year old make this for his school science fair. While I do wish the supply list were more detailed - including the sizes for things, and how the craft sticks, cubes, and beads should all be the same width - the two of us managed to put this together in about an hour and a half, which includes letting the hot glue dry between steps. Even though ours isn't pretty, and the fingers aren't perfectly even or nice and neat, this thing still has grip! My son demonstrated this by picking up a &quot;lightsaber&quot; made out of a foam pool noodle. <br><br>The instructions and photos were straightforward enough that my son understood what to do, and once it all started coming together he had no problem figuring out how it all worked together.<br><br>FWIW, we used regular Scotch tape to hold the trigger and hinge in place and duct tape to attach the skewer to the back of the hand. Instead of buying wood skewers I cut some wire hangers to the lengths we needed. We didn't have a cable tie, so I used a Velcro wrap to keep the skewer on the arm. The craft sticks we used are 4 1/2 in. long x 1/2 in. wide, and we used half-inch rounded craft beads for all the joints instead of blocks. The arm is 3 sticks long, which is perfect for my 7-year old. </p>
<p>Wow, thanks for sharing! I'm glad to hear that you super successful!</p>
<p>fantastic idea...its quite helpful especially for the elderly people, so thumps up..!!</p>
<p>does this actually pick things up? Is it a lever?</p>
<p>It was great to do it, and I made one only enhacement, that I took a picture. Thank you... I have a lot of fun...</p>
Wow, this is awesome! Thanks for sharing - it's really cool to see others actually make use of these project plans :)
<p>extremely awesome</p>
<p>Simply Wonderful.</p>
That's awesome
<p>Awesome! This would work great for a puppet hand :D thanks for sharing!</p>
<p>Good work! Maybe you could add a video.</p>
<p>So great!! Thanks for posting. </p>

About This Instructable




Bio: I've authored Rubber Band Engineer and Duct Tape Engineer. Click on my website to learn about them. For a master list of materials for ... More »
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