Astonishing Science. Spectacular museum.
Remould a plain bar of soap into an attractive new shape you can still use in the bathroom!
Year groups: 3–9 (ages 7–14)
To develop, as a group, the ultimate remoulded soap recipe and design and produce soap.
Download student activity sheet [pdf]
There are many ways you could choose to run this activity, but the format suggested below will spread over about two sessions.
Evidence suggests people have been making soap since 2800 BCE. Over the years and with new scientific discoveries approaches to making soap have changed, as have its uses. It has now become an everyday item rather than a luxury product.
Bar of 'Sunlight Soap' c.1890-1914
Chocolate behaves in a similar way to soap: when you heat it the bonds between the molecules change so that it becomes more like a liquid; when it is left to cool down it returns to its original form.
A chocolate factory at work, Liebig trade card, early 20th century.
Soap is made up of sodium or potassium salts of fatty acids. It is an alkali that also contains glycerol.
When hot water is added to the soap, the heat of the water affects the bonds between the soap molecules, allowing them to move more easily and making the soap mouldable. This is a reversible change and is a result of the type of bonds within the soap. As the soap mixture cools down the bonds begin to return to their original form, giving it a more solid structure which solidifies further when the soap is left to dry, as the water content slowly evaporates. You can melt grated soap over a heat source rather than adding hot water, but we recommend the method above as it is easier and safer in the classroom. There are other materials that behave in a similar way, including chocolate.
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 2 and 3 STEM (Science, Technology, Engineering and Maths) clubs to provide enrichment and extension of the curriculum. However it may also be used for teaching other elements of the curriculum at KS2 and 3 in an engaging, inspiring and memorable way.
SC1 Scientific enquiryInvestigative skills – planning
Considering evidence and evaluatingStudents should be able to:
SC3 Materials and their properties Grouping and classifying materials
Key concepts 1.1. Scientific thinkinga. Using scientific ideas and models to explain phenomena and developing them creatively to generate and test theories. b. Critically analysing and evaluating evidence from observations and experiments. 1.4. Collaborationa. Sharing developments and common understanding across disciplines and boundaries. Key processes2.1. Practical and enquiry skillsa. Use a range of scientific methods and techniques to develop and test ideas and explanations. b. Assess risk and work safely in the laboratory, field and workplace. c. Plan and carry out practical and investigative activities, both individually and in groups. 2.2. Critical understanding of evidencea. Evaluate scientific evidence and working methods. 2.3. Communicationa. Use appropriate methods, including ICT, to communicate scientific information and contribute to presentations and discussions about scientific issues.
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