STEM Labs
Loop, There It Is!

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Now that you've finished the build, test what it does. Explore your build and then answer these questions in your engineering notebook.

Where is the pivot point (the point the robot rotates about) for this robot build?

• Make a prediction and then manually move a wheel on one side forward while at the same time moving a wheel on the opposite side backwards at the same rate.

After manually moving both wheels, now describe where the pivot point is. How would the pivot point of the robot change if the Build design was changed so both of the wheels that are not attached to motors did not use gears?

• For further explanation, notice how when one wheel is moved on one side, both wheels move because they are connected using gears. If they were not connected using gears and the wheels not connected to motors moved freely, how would that change the pivot point of the robot?

Explain how a robot’s pivot point could change its behavior.

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Answers should include the pivot point moves from between the two drive wheels when only 2 wheels are powered without the use of gears. It will then move to the center of the robot when all 4 wheels are powered using gears.

Many explanations are acceptable, such as a robot might smash into an object if only one set of wheels are powered as it turns, but it will spin in a circle if all the wheels are powered using gears where one side is moving forward and the other side in reverse.