Read the instructions.

For this experiment, you will need a chemistry beaker or a tall, clear plastic container. You will also need a shallow pan, ¼ cup of baking soda, and ½ cup of white vinegar. Begin by placing the container in the pan. Next, pour the baking soda into the container. Then, pour the vinegar into the container. If the experiment is successful, the resulting solution should foam out of the container and overflow into the pan.

Which structure of a procedural text is missing from these instructions?

goal
method
materials
evaluation