How Things Work
The spinning square
Make a spinning square and watch what happens.
In your book, Our Wondrous World (Chapter 7), the third spinner Meera and Dhruv try is made from a square card. A square has four straight sides and four sharp corners.
But when the square spinner spins, something surprising happens: it looks circular! While it is spinning fast, you do not see its corners any more. It looks like a round circle.
The card has not really changed its shape. When the spinner slows down and stops, you see the square again, with its four corners. Your book asks you to try spinners of other shapes too, and see what happens.
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