How fast does hair grow?

The story of Rapunzel and her long, golden hair has been told for centuries. But just how long is her hair, and how long did it take to grow?

In this lesson, students will explore these questions with the help of a real-life Rapunzel named Ida Pedersen, who hasn’t cut her hair in over a decade. They’ll use linear equations to model how her hair has grown over time, and will use their model to estimate a person’s hair growth rate. Based on this, they’ll be able to see whether or not Rapunzel’s story is true to life, or whether there must be something more magical going on.

- Construct a scatterplot from empirical data of hair length over time
- Estimate a line of best fit, or calculate one using linear regression
- Make predictions about hair length at a given time using proportional reasoning
- Given hair length and time, calculate the unit rate of growth
- Construct graphs that model hair growth in different scenarios

- Rulers

Ida Pedersen, Rapunzel