What's Going On?

Top of the pops

Activity overview

Science topics:

Materials, States of matter

Spark a conversation with this video showing some explosive kernels! This activity is great for describing observations and applying ideas in unfamiliar contexts.

Run the activity

1. You’re going to watch a short video. The aim isn't to find right answers, it's to explore ideas and find out what they know.

  • Do they know what might happen based on the image?

2. After you've watched the video, lead a discussion with your class:

  • Do they know they're looking at popcorn?
  • How do they expect the kernels to behave?
  • What do they notice changing during the film?
  • Do they know they're watching an irreversible change?

3. Ask the class to describe what they saw using only one word.

Background science

There are four types of popcorn and only one type has a thin enough husk, or outer shell, to pop. Each popcorn kernel contains a small amount of water stored in the centre.

To make popcorn pop, you need to heat the kernel to boiling point so that the water inside turns to steam, which builds pressure inside the kernel until it bursts through the husk. The heat also changes the structure of the kernel so that it's light and puffy. A single kernel of corn can swell to 40-50 times its original size! 

Take it further

Keep exploring the world of reactions and expanding gases with this Balloon Surprise activity. Or if you have the right equipment and access to a microwave, make some popcorn!