In STEAM club this week, the girls made their own bath bombs using only two ingredients!

Sodium bicarbonate (also known as baking powder) is a weak alkaline that doesn’t fully ionise in water. It needs a little help to foam up and this where the citric acid comes in. Citric acid is commonly found in citrus fruits such as lemons and oranges. As you can tell from its name, it is a weak acid. When citric acid is mixed with sodium bicarbonate, a chemical reaction occurs called neutralisation. The chemicals that are released are carbon dioxide and sodium citrate. As the carbon dioxide escapes quickly, this causes small gas bubbles to appear. And this is what causes the bath bombs to fizz!

The girls added different colours and fragrances to their bath bombs to make them smell and look relaxing. Some opted for fresh linen, coffee or a jasmine scent and some even opted for a hot apple pie scent! They then pressed their bath bombs into the moulds and put them aside to set.