These activities help children practice sorting by size.
Sorting Pom Poms
Pom poms from a craft store can be purchased in a variety of sizes. Children sort them into small, medium, and large jars.
Sorting Craft Punches
These stars were cut from small, medium, and large craft punches. If you do not have those available, clipart could be printed in different sizes for this activity. Children glue them onto small, medium, and large paper.
These were fairly inexpensive at a hardware store. I bought 3 boxes with 3 different sizes of bolts. The 3-sized cups came from a set of stacking cups.
Children sort the bear manipulatives into the small, medium, and large jars. We also sometimes use the Bear Family printable.