Introduce perimeter and area.
Perimeter = the outside edge
Area = the area inside
After you have all acted like t-rexes, tell the kiddos they will find the area and perimeter of each pentomino, searching for the MAGIC pentomino that is unlike the rest. There is only one. Here's what my kiddos' science notebooks liked like during the activity.
Which pentomino is magic? This little baby! It has an area of 5 and a perimeter of 10!