[servo whirring]

I'm Daisy from Design Squad, and I'm here with...

(Anna) We will make a robotic arm using cardboard, string and straws.

(Ethan) NASA uses robotic arms because lots of its missions don't involve people. Also, mechanical arms are much stronger than human arms.

(Daisy) Our robotic arm needs something flexible, something that can be pulled without breaking, like string. String is good in tension. It also needs something rigid for the bones, like cardboard, which is good in compression.

(Arun) Robotic arms are like human arms. They have a hand, forearm, and upper arm.

[whistles]

People don't need string to move fingers because they have arm muscle to pull their tendons. Sometimes things don't go the way you want them to. So if you pull this string, it moves this way. That's awesome. The cool thing about robotic arms is its system of levers. When you pull, the sections move around the pivots, making the end of the arm move. A baseball bat is a lever. You put force in one end and get movement in the other. If you pull this, it should move backwards, but it doesn't.

(Anna) The string gets bunched up. Use fishing line. It's more slippery.

[Daisy] Pick something up.

I need to find something to hook it around. Okay.

Yeah! [laughing]

I got it! Let's see if these robotic arms can pick up some space rocks. Make it higher. Yes! We got it! Yes!

(Daisy) For how to make this and to see activities related to NASA's missions, visit the Design Squad website.

[laughing]

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