The wire was wound on a pencil making 30 turns to determine the diameter.

In physics, there is a way to measure the sizes of small ones, which is called the method of rows.

In this experiment, you need to apply this method.

To determine the diameter (wire thickness), you need to measure the distance between the outermost turns. Then divide this distance by the number of turns (by 30). The result is the diameter of the wire.

Note: to increase the accuracy, you need to increase the number of turns, and place the turns more densely.