I have been imploding watermelons with rubber bands with my Year 7 science classes for over two years. The kids absolutely love the experiment. We work as a class to patiently place rubber bands onto a large watermelon one at a time and revel in being suddenly splashed by pieces of watermelon. Here is a video of our experiment. See The Big Watermelon Experiment for details on how to do the experiment.
Imploding a watermelon with rubber bands is also a great way to teach how to write explanations in science. I like to use a cause-and-effect graphic organiser to teach students how to use forces to explain what happens in the watermelon implosion experiment. It’s a great opportunity to teach how to use scientific concepts to explain observations. After the graphic organiser, I like to use an explanation scaffold to support students to write an extended text that sequentially explains how rubber bands can implode a watermelon. In this activity, they use casual connectives, time connectives and rhetorical questions. It’s also a great way to embed any paragraph structures your school prefers like TEEL or PEEL.
Use the link below to download and adapt the writing scaffolds for your students.
If you have done the watermelon implosion and/or used the experiment as an opportunity to develop your students’ writing skills, please comment below to share your experience.