What's Going On?

Baking cookies

Activity overview

15 mins
Ages 9 – 11

Science topics:


Spark a conversation with this video showing the transformation from cookie dough to delicious snack. 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:

  • What's in the oven?
  • What are the main ingredients in cookies? 
  • Can they explain why the cookie mixture reacts in the way it does?
  • Do they know that this is an irreversible change?

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

Background science

Baking cookies is an example of an irreversible change. Most foods when cooked undergo what is known as the Maillard reaction, which results in food browning. Sugars also become caramelised when exposed to heat. Both the Maillard reaction and caramelisation are irreversible changes and result in the production of very pleasant aromas. Who can resist?

Take it further

Ask the class if they know which ingredients go into making cookies. What do they know about the ingredients that helps explain what they saw?

This BBC video explores irreversible reactions. 

Video credit:

Beachfront B-Roll (CC BY);

image credit:

Steve Cukrov via Shutterstock