This is a lesson which meets specification points within the WJEC GCSE ‘The Sciences’ Double Award (2026) spec, specifically from Unit 2.3 Rate of Reaction (Chemistry).

The lesson begins with an introduction to the investigation. The rate of a chemical reaction can be changed by altering different factors, including temperature, concentration, catalysts, and surface area. In this investigation, you will explore how changing the surface area of calcium carbonate affects the rate of reaction with hydrochloric acid.

When a solid is broken into smaller pieces, more particles are exposed and available for collisions. This increases the frequency of successful collisions between reacting particles, causing the reaction to happen faster. You will compare different sizes of calcium carbonate chips and measure the volume of carbon dioxide gas produced using a gas syringe to determine how surface area affects the rate of reaction.

The next couple of slides outline the equipment needed and the method list for this investigation. Students will then ‘Think > Pair > Share’ their ideas about a results table should look like. After a class discussion, the teacher can draw some example tables on the board so students have an idea about what they need to include for their results table.

After this, in pairs/groups students should have another discussion about the control variables and potential sources of error in the investigation. Some examples for each of these are included in the PowerPoint for the teacher to go through.

Now, students can complete the investigation, recording their results as they go. Once complete there are a set of analysis questions for them to answer, based upon the results they have collected.

All resources are included. Thanks for looking, if you have any questions please let me know at swyftresources@gmail.com and any feedback would be appreciated.