Measure 100 ml of tap water using the graduated cylinder and pour it into the first beaker.
Add 3.5 grams of salt into the first beaker along with a few drops of food coloring. This should make the solution a fairly deep color. This creates a 3.5 percent salt solution (3.5 grams per 100 ml).
Measure 50 ml of salt solution from beaker number one and pour it into a new, empty beaker (number two). Add 50 ml of tap water to this solution. This creates a 1.75 percent salt solution, your first dilution. This is half as much as the first solution.
Measure 50 ml of salt solution from beaker number two and pour it into beaker number three. Add 50 ml of tap water to this beaker. This creates a 0.875 percent salt solution, half as much as beaker number two. This is your second dilution.
Measure 50 ml of salt solution from beaker number three and pour it into the last empty beaker (number four). Add 50 ml of tap water. This creates a 0.4375 percent salt solution, which is half as much as beaker number three. You can continue this process in order to make a serial dilution for any solution. The color of the food coloring should become lighter with each dilution.