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Make your own bath fizzers and see whose fizzes the most!
Year groups: 3-11 (ages 7-16)
For each student to make two bath fizzers and test their performance, investigating the best proportions of ingredients to get the ultimate ‘fizz’.
Download student activity sheet [pdf]
Bath bombs or bath fizzers are sold in many cosmetics shops around the world. They are therapeutic during bathing because of the essential oils that they contain and are also used for cleansing.
Effervescent vitamin C tablets use a reaction to create ‘fizz’ in a similar way, to disperse the contents evenly throughout a glass of water.
Bath fizzers fizz in water because the sodium bicarbonate reacts with the citric acid. This releases bubbles of carbon dioxide and produces a salt and water:
The reaction only starts when the two dry chemicals dissolve in the water – i.e. it is the solutions reacting. However, when you add any liquid, such as food colouring, to the mix, then your mixture may begin reacting early. You can use the activity to introduce the idea that dry chemicals and solutions can behave differently.
Witch hazel is a suitable liquid to use when moulding the fizzers as it evaporates quickly. The witch hazel solution only minimally dampens the dry ingredients for a short time, conserving the ‘fizz’ for when you want it in the bath!
These resources support integrated Science, Technology, Engineering and Maths activities in STEM clubs. Here are some specific links:
This resource has been developed specifically for use within Key Stage 3 STEM (Science, Technology, Engineering and Maths) clubs to provide enrichment and extension of the curriculum. However it may also be used for teaching elements of the curriculum at KS2 and KS4 in an engaging, inspiring and memorable way.
We do not recommend this resource for use with children younger than KS2 owing to the safety requirements.
Science Curriculum links from QCA guidance for England.
This activity also provides a great opportunity for cross-curricular learning linked to Art, Design, Maths and ICT (which could be used to record results and/or design and produce packaging).
This activity supports delivery of How Science Works as it allows pupils to explore science in use in the ‘real world’ in a product they may have personal experience of. It allows them to experience the scientific method and to understand that different scientists will have different views of the ‘best’ result (when coming up with their fizzer formula different student groups may set different criteria for success). They will also learn to apply some key concepts about rates of reaction and reaction between acids and bases (neutralisation).
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