Using Fractals and Turtle Geometry to Visually Explain the Spread of a Virus to Kids: A STEM Multitarget Activity.

A lockdown was ordered in Spain on March 2020 due to the COVID-19 pandemic. The first author, advised by the second author, developed a tale and video (in Spanish) with a simplified explanation of virus propagation for their teenager son, justifying the need to stay at home. The tale and video relate the spread of the virus to fractal trees and aim to raise awareness about the transmission of the disease. The video is available from the web page of the Instituto de Matemática Interdisciplinar of the first author's university. The code was implemented in Scratch 3 and takes advantage of the "Turtle Geometry" (there is an ulterior version using Maple, available from Mapleprimes). This article includes the English version of the original tale, describes the Scratch 3 code, and details possible derived STEM activities. We plan to experiment them in the classroom during the 2020–2021 academic year. [ABSTRACT FROM AUTHOR]