Materials

• 2 bananas

Instructions

• STEP 1: Make sure the bananas are exactly the same size. Hold one of the bananas above the other, lining up the two left ends, and observe.
• STEP 2: Switch the bananas and observe. Is one longer than the other? Construct an argument on how your eyes, an external structure, work with your brain, an internal structure, to support survival, growth, behavior and reproduction.

Explanation

The bottom banana looks longer when compared to the top banana. Although each banana is exactly the same size, your eyes compare the bottom arc of the top banana to the top arc of the bottom banana, which is longer. This tricks your brain into believing the bottom banana is longer.