Ms. Frizzle's fantastic science fun is now available for younger fans of the bestselling science series ever! The new Magic School Bus Scholastic Readers make learning an adventure! Wanda finds a tooth in the back of Ms. Frizzle's classroom. It is small and very sharp. It doesn't look like a human tooth. Who lost it? The Friz thinks a field trip is in order to explore what teeth do and why they have different shapes. Take off on the Magic School Bus for an adventure with lots of bite, and find out all about teeth!