Emulsifiers

This resource should take approximately one hour to complete in full. It was initially created for 11–14 year-old learners but can be adapted for other age groups. Use the activities in a sequence of timetabled lessons, science clubs or as part of an off-timetable, enrichment day. 

Learning objectives

• Explain how soap acts as an emulsifier in cleaning.
• Explain how emulsifiers are used to make hand creams.

Guidance notes

Use the PowerPoint presentation to introduce soap and its history.

Explain and show how oils and water normally don’t mix with the demonstration. Add an equal amount of water and vegetable oil to a large plastic bottle so that they form distinct layers. Gently shake the bottle and show how the layers do not mix. Even when they do, they will separate out again, given time. Add a small amount of washing-up liquid and shake the bottle. The oil and water will now mix. Use this to explain how the washing-up liquid acts as an emulsifier in this demonstration and how soap cleans by forming an emulsion.

In Activity 1, learners will work in pairs or small groups of three to produce their own hand cream using the method provided in the student workbook. Remind learners not to use the hand cream they make. Be aware of any allergies prior to completing the activity.

They will then examine their hand cream under a microscope in Activity 2. Tell learners they will look at the sample of hand cream they made in greater detail and draw it. They should be able to see how the oil droplets are spread throughout the mixture. Learners may need support in using a microscope, depending on whether they have used one before.

Find the answers in the teacher notes and on the slides. 

This resource was developed as part of the Chemistry for All project. The project was set up to explore and address barriers to participation in UK chemistry undergraduate study through a longitudinal project. Read the findings relevant to teachers, outreach providers, education policymakers and parents in the summary report, or download the full research report.

Health and safety

Read our health and safety guidance and carry out a risk assessment before running any live practical.

The safety equipment suggested is in line with CLEAPSS requirements. For non-hazardous substances, wearing lab coats can help to protect clothes. The safety rules might be different where you live so it is worth checking local and school guidance.

Be aware of any allergies before carrying out the activities.

Careers

The Chemistry for All project found that recognising the value and importance of chemistry, and appreciating how chemistry can lead to interesting and well-paid jobs strongly related to learners’ future aspirations. Discover how chemistry can prepare learners to pursue apprenticeships, university courses and vocational routes, or browse job profiles and try our career options game from A Future in Chemistry.

After the introduction, highlight chemistry careers making a difference, such as senior scientist in household goods. Phillip’s job profile explains how he leads a team of researchers to improve the quality and performance of household products such as soaps and shampoos. Watch the video job profile on slide 9 of the PowerPoint and discuss other careers such as Robert’s, a consumer products technician. He develops materials to improve the properties of household products such as washing up liquids and soaps.

Find more activities like this, plus longer projects suitable for off-timetable days, science lessons or clubs on our Outreach resources hub.