A card spinner

In your book, Our Wondrous World (Chapter 7), Meera and Dhruv make their own spinners. You need pieces of cardboard, some toothpicks, and an empty tube of a ballpoint pen. You push a toothpick through a piece of card, then spin it like a top.

They try two spinners. In the first, the toothpick goes through the very centre of the card. In the second, the toothpick goes through a hole away from the centre.

The first spinner, with the hole at the centre, looks the same from all sides. It stays upright and spins. The second spinner, with the toothpick away from the centre, does not spin properly. So where you make the hole makes a big difference.