Education Technology

Watermelon Volume

Activity Overview

There are several ways you can work out the volume of a watermelon. This activity explores three different ways and in the process, improves student understanding of the approximation approach (slices) and the calculus formula. 


The aim of this activity is to create a fun and delicious way for students to learn, understand and remember how to calculate the solid of revolution. By literally slicing up the solid, approximating each slice as a cylinder, measuring each slice and adding them up, students make the connection with the theoretical volume, determined by a solid of revolution.


  • Solid of revolution
  • Approximation
  • Slice
  • Sum

About the Lesson

Students determine the first estimate for the volume by submerging the watermelon, using Archimedes' principle .The watermelon is then measured, photographed and inserted as a background image ready to be modelled. The watermelon is then cut into slices, students measure the volume of their cylindrical slice and estimate the volume by summing all the slices. Locating their slice on the graph helps students associate the 'solid of revolution' and the alignment of the radius with the function. The numerical sum is then extended to a calculus approach. A deliciously fun and memorable way to learn calculus.