Investigate the science of baking

Testing cake ingredients in an ice cube tray


Do you ever wonder how and why cake batter rises in the oven? The answer is science. Or chemistry to be more precise! The way in which different ingredients react with each other affects how a cake turns out. 

When certain ingredients are mixed the resulting chemical reaction produces gas. In this experiment you’re going to test some common cake ingredients to work out which ones produce the air bubbles needed to make a cake light and fluffy.


You will need:

  • Paper
  • Pencil
  • Ruler
  • Flour
  • Baking Powder
  • Bicarbonate of soda
  • Vegetable oil
  • Water (cold and hot)
  • Vinegar
  • Milk
  • An ice cube tray or small dishes
  • A spoon


Grid showing all the variables to record results of experiment


1. Start by drawing a grid on your piece of paper and marking the rows and columns with the ingredients you will be testing: flour, baking powder, baking soda, oil, hot water, cold water, vinegar and milk. 

2. Place an X in each box where the ingredient in the row and column are the same - you won't need to test these combinations!

3. Before you start, make a prediction about what you think might happen. Which ingredient combination do you think will give the biggest reaction? What makes you think that?

Recording observations on the grid


4. Working logically, combine a small amount of two ingredients in a section of the ice cube tray, stir together and watch what happens. Record what you’ve observed on your grid. 

5. Continue combining two ingredients at a time in an empty section of the ice cube tray and observing the reactions. If you need to wash out the ice cube tray part way make sure you’ve recorded your observations before washing and drying it thoroughly.

6. Once you've tested every possible combination your experiment is over (note: each combination appears twice on your grid but you only need to test it once!) 

7. Finally, it's time to look at your results and see what you've learned. Have a think about these questions:

  • Which ingredient combinations do you think would be most likely to create a light and fluffy cake filled with air bubbles?
  • In what ways are baking powder and bicarbonate of soda similar and different?
  • Can you think of any other ingredients you’d like to test? (If yes, why not have a go and add your results to the grid?)


Congratulations, you’ve conducted a science experiment! If you take a look at your favourite cake recipe you'll now know why they've included certain ingredients.

If you want to learn a bit more about the science of baking, you might also enjoy this video: