The procedure is a detailed, step-by-step list of everything you will do in your experiment, including the materials and methods you will use. When writing, be specific enough so that someone could repeat your experiment and reach the same results. Then have someone else read your procedure to make sure it makes sense to them.
Make sure to include the following details in your procedure:
Materials and equipment. Describe all of the materials and equipment you will use in precise detail, such as “one 5 volt battery”, or “two 32-ounce plastic bottles.”
Sample. The sample is the group of people who you select to be in your experiment, if you are using human subjects. Describe how you will choose your sample. A random sample is preferred because it represents a wider range of the population than if you chose friends, family, or neighbors to be in your sample.
Methods. Write out the steps in your procedure clearly, like a recipe. Describe how you will document and observe your experiment as you carry it out (measurements, notes, sketches, photos, etc.). Include the number of times you plan to repeat the experiment. This is called the number of trials.
Variables. Describe each of the variables and make sure you include their measurements or quantities at the start of the experiment. Describe how you will change the independent variable, and how you will measure its effect on the dependent variable. Also explain how you will keep the control variable constant.