Disassemble a Click Pen

On occasion, engineers find an item or even design something without fully understanding how or why it works. When this happens, it is helpful to work backwards by analyzing the finished design to see how the parts work together. Performing reverse engineering by analyzing the interactions between parts contributes to a better understanding of how something works.

• How a pen works by taking it apart, analyzing its components and its function.
• How different components of a system work together to reach a desired function (in this case, a retractable ballpoint pen).
• The value of learning by disassembling products to discover how they work.
• Recognizing a design requirement (such as capped pen vs. click pen).
• Skills: analyzing and organizing variables to investigate how a system works, technical discussion about how the object works using new vocabulary.
• Other potential learning areas: compression of a spring, history of writing utensils.

One of the best ways to learn about how something works is to take it apart and look at the pieces and see how they are connected. It's something we call "reverse engineering."

Unfortunately, with technology getting smaller and more complex, this method becomes increasingly more difficult. One device that has managed to stand the test of time is the click pen. Let's take a closer look.

Background

A recommended resource: A thorough description of ballpoint pens and how they work: http://www.howstuffworks.com/pen.htm

Before the Activity

• Obtain a supply of twist-apart retractable "click" pens, one per student.
• Make copies of the two worksheets and the grading rubric.

With the Students

1. Ask some focusing questions.
2. Before handing out the pens, have students complete the Click Pen Investigation Worksheet.
3. Distribute copies of the Click Pen Diagram Worksheet. Discuss the two views presented. The cross-sectional view shows only the barrel and the cap, but there are many other parts in this pen.
4. Distribute copies of the rubric.
5. Hand out the pens and give students time to carefully disassemble their pens.
6. Have students draw in the missing parts in the cross-sectional diagram and label them.
7. Encourage students to explore possible ways to make the pen work/not work by removing (and modifying?) parts.
8. Have students write in their journal. Prompts: "Choose one part of this pen and describe how it works in words and drawings." Or, "Can you make this pen simpler or cheaper by leaving out any parts? Explain in writing and drawings."

Rubric for Performance Assessment (doc) (DOC)

Rubric for Performance Assessment (pdf) (PDF)