Description orients readers to objects and processes. Your goal is to make the readers feel in control of the subject.

• Show readers how this subject fits into a larger context that is important to them.
• Tell them what you are going to say; write this kind of document in a top-down manner.
• Choose clear heads; write in manageable chunks; define terms sensibly; use visual aids that helpfully communicate.
• Choose a tone that enables readers to see you as a guide.

Mechanism descriptions. In the introduction

• Define the mechanism and tell its purpose.
• Provide an overall description.
• List the main parts.

For each main part

• Define the mechanism and describe it in terms of size, shape, material, location, color.
• List and describe any subparts.

Process descriptions. In the introduction you need to

• Tell the goal and significance of the process.
• Explain principles of operation.
• List the major sequences.

For each sequence or step

• Tell the end goal of the process.
• Describe the action in terms of qualities and quantities.