An experiment to investigate the effects various ions on a soap solution
Method
2cm3 of distilled water was taken. This distilled water was pre-mixed with the concentration of the appropriate ion (e.g. Sodium ion, Magnesium ion, etc.) After this, 30 drops of soap was added to the compound in the distilled water and the resulting solution was viewed to examine whether lather or a scum was formed. If lather was formed then foam would form on the top of the solution. If a scum is formed, then you would see a solid floating in the solution and the water would turn opaque.
Variables
Independent Variable
An independent variable is one which you chose to change and is independent of anything else. For example the independent variable in this experiment is the substance in the solution, which will be constantly changing in the experiment.