1.
Cut a hole in the center of the paper plate; this will make the hat's brim. In order to determine the size of the hole, measure the inside rim of your soup bowl. Also, place the plate on your child's head once you've cut the hole to make sure it will fit.
2.
Paint the bowl and the paper plate green. Lay down some newspaper and wear a smock to catch any paint messes. Paint the top and bottom of the paper plate, and the outside of the bowl; you don't have to paint the inside of the bowl because it won't show.
3.
Set the bowl and plate aside to allow the paint to dry.
4.
Once the paper plate and the bowl are painted and dry, glue the lip of the bowl to the paper plate. Make sure the rim of the paper plate is facing up to make the brim of the derby hat like shown in the photo below.
5.
Add a hat band. If you're using tissue paper (rather than felt or ribbon) twist 2 or 3 pieces of green tissue paper together with your fingers, and glue it to the hat in several places so it stays twisted. If you don't want to use tissue paper, use ribbon, felt, or construction paper to make a flat hat band.
6.
Use a cookie cutter to trace a shamrock on construction paper and cut it out. You can draw your own shamrock if you don't have a pattern.
7.
Glue the shamrock to the hat band for good luck.