A special purchase of three stuffed bears was not necessary. As most moms will attest, stuffed animals seem to mysteriously MULTIPLY in a home with children. The kids seem to receive them as gifts, win them at church picnics, and before you know it, you have a house overrun with stuffed critters! For the bears used for this lesson, I just searched through the collection and found three of different sizes, and off to school they went. If you don't have children of your own, try asking a mom you know...she'll probably be glad to donate some bears for you to use!
Next, I give each of the three bears to three students to hold while I begin reading the story. There are many versions of this well-known story. Three books pictured here are authored by Caralyn Buehner, Jan Brett, and James Marshall. Each time the bears say their phrases ("Who's been sitting in my chair?", "Who's been eating my porridge?", etc), I give the child who is holding the bear a chance to speak in each bear's vocal timbre. After speaking in their low, medium, and high voices, the students pass their bear on to another student to have a turn.
Squidoo.com has a terrific selection of different Goldilocks and the Three Bears coloring pages) and label them with the words low, medium, and high. If your students have difficulty with printing, you can pre-print their pages with these labels. When they are finished, make them a part of a student-created bulletin board!