I've collected together lots of different balls that are used in various sports:
Here are the standard diameters of the different types of ball:
Here is a scale drawing I've done of the balls:
You might like to find a few different balls at school to get a feel for their different sizes before trying this challenge.
Try using the diameter information to make circles the right size and use them to explore.
If a line is drawn on the ground and the balls are put on that line with each ball touching the one in front and the one behind, which arrangement makes the shortest line of balls?
Which arrangement makes the longest line of balls?