‘Lather Depth’ method

• 1. Measure out fixed volume of a water sample to a boiling tube and add a measured fixed volume of soap solution.
• 2. Put a bung in the top of the boiling tube and shake the mixture vigorously for 5 seconds.
• 3. Measure the depth of the layer of lather that forms in the tube and repeat these steps for other water samples.
• 4. Compare the lather depth for each sample - sample with the smallest lather depth is the hardest sample of water.
• Lather Practical