Add equal volumes of oil and water to a the test tube, followed by the emulsifier you are using. measure out the amount of emulsifier by adding it dropwise from a pipette – ten drops is a good starting point. Each experiment should use the same volume of oil and water, but add another ten drops each time.
Once you have everything in the tube put your thumb over the end and give it a shake so everything mixes. Once you stop shaking start the timer and wait until the oil and water have completely separated. Using coloured water can help you see the difference a bit more clearly.
When you finish make sure to clear down your work area and rinse out the test tubes you have used.
Record the time for each experiment and then use this information to plat a graph to show how the volume of emulsifier affects the time taken to separate.