Dottie Frizzle is Ms. Frizzle's cute and pretty niece. She appears in The Magic School Bus and the Electric Field Trip. She has red hair and is about the same age as the students in Ms. Frizzle's class. Dottie wants to grow up to be just like her lovely aunt, but Arnold thinks she already is. She is the daughter of Ms. Frizzle's brother, John.
On the same day that Ms. Frizzle chose to teach her class about electricity the class had a new visitor. The visitor was Ms. Frizzle’s niece Dottie and when she found out the class was learning about electricity she seemed to share the same excitement for science that Ms. Frizzle does. Ms. Frizzle began teaching the lesson on electricity in the classroom when a flash of lightning turned the power off. The students and Ms. Frizzle loaded on the school bus and headed to the power plant to learn about electricity in a very hands-on way. The class traveled through a steam pipe, in a light bulb, and through a power line. The class now understood electricity because they had seen it, inside and out.