Summary

In this lesson students will learn about the mechanisms and properties of airbags, and examine the choice of airbag inflator from several points of view.

Grade Level

High school

NGSS Alignment

This lesson will help prepare your students to meet the performance expectations in the following standards:

• HS-ETS1-1: Analyze a major global challenge to specify qualitative and quantitative criteria and constraints for solutions that account for societal needs and wants.
• HS-ETS1-2: Design a solution to a complex real-world problem by breaking it down into smaller, more manageable problems that can be solved through engineering.
• HS-ETS1-3: Evaluate a solution to a complex real-world problem based on prioritized criteria and trade-offs that account for a range of constraints, including cost, safety, reliability and aesthetics as well as possible social, cultural, and environmental impacts.
• HS-PS1-2: Construct and revise the explanation for the outcome of a simple chemical reaction based on the outermost electron states of atoms, trends in the periodic table, and knowledge of the patterns of chemical properties.

Objectives

By the end of this lesson, students should be able to

• Explain the mechanism of an airbag, and how it protects an occupant in case of an accident.
• Justify the use of an airbag design system based on analysis of different stakeholder perspectives.

Chemistry Topics

This lesson supports students’ understanding of

• Chemical reactions
• Stoichiometry
• Gas laws

Time

Teacher Preparation: 20 minutes

Lesson:

• Engage: 5 minutes
• Explore: 40 minutes
• Explain: 80 minutes
• Elaborate:40 minutes
• Evaluate: 40 minutes

Materials

• Students will need to register on the infographic site that you chose. Each of the suggested sites below allow free individual registration.
  • Piktochart
  • Canva

Safety

• No special safety considerations are required in this activity.

Teacher Notes

• This resource could be used as a post-AP Chemistry exam activity.
• Engage: Before showing the video, start by asking the class if anyone knows what gas is inside an airbag when it expands, and where this gas is stored in the car. Students may be surprised to learn that the gas is formed as a result of a chemical reaction. The video does a good job in showing the rapid expansion of the airbag. There is a second video which also can be shown which explains the chemistry of the airbag deployment and is an excellent companion to the first:

Video on Airbag Deployment (~4 minutes in length)

Optional second video (~ 2 minutes in length)

• Explore: The students will begin the research portion of the “Depicting Airbag Chemistry and Technology in an Infographic” assignment (Student Activity-1). Web sites listed on the student handout are a good starting point for airbag technology. Other web sites or articles can be used to supplement these resources.
  
  
• Explain: Students are asked to incorporate their research into an infographic that will be posted in the classroom. This is best done collaboratively in groups of 2 or 3. Both Piktochart and Canva offer free individual accounts and the ability to print or upload the infographics. Canva also offers the ability to save the infographic as a PDF. Students can either be directed to one site, or offered the option to pursue either. Kathy Schrock has an excellent 2 minute video, which gives tips for creating an infographics. As a minimum, before beginning this project, students should be aware of copyright restrictions on using others’ graphics and pictures.
  
  
• Elaborate: Students are shown the NBC news video about the Takata airbag recall. They are asked to take on different roles in the classroom as presented on “The Future of Airbag Technology” student handout (Student Activity-2), and think about future airbag development. From their perspectives, they brainstorm lists of criteria needed for the development of new airbag technology. Each group is asked to read a new set of web resources about airbag technology and develop a list of criteria needed for airbags of the future. The class then meets together to discuss the lists generated by the different groups. The Takata airbag technology hinged on the use of ammonium nitrate as a source of nitrogen gas. Students should be aware of this so they can discuss the pros and cons of alternate chemistries.
  
  
• Evaluate: Kathy Schrock has an excellent rubric for infographic evaluation, which is free to reproduce for classroom use: Copies of this rubric can be given to a student, and they can circle their evaluation of another students’ work using the rubric. Points can then be assigned to each descriptor and category, and totaled for each infographic. This would allow each infographic to be evaluated in the classroom.

References

• http://auto.howstuffworks.com/car-driving-safety/safety-regulatory-devices/airbag.htm
• http://automotivesafetycouncil.org/resources_passive.asp?videoID=55#17
• http://sciencenetlinks.com/lessons/its-a-crash-test-dummy/
• http://www.carfax.com/guides/safety/airbag-technology
• http://illumin.usc.edu/88/the-engineering-behind-automotive-airbags/
• http://www.reachoutmichigan.org/funexperiments/agesubject/lessons/newton/airbags.html
• https://www.youtube.com/watch?v=SSz6y-W-R_A&nohtml5=False
• http://www.nbcnews.com/business/autos/takata-airbag-recall-largest-u-s-history-just-got-even-n568106
• http://www.chemistry.wustl.edu/~edudev/LabTutorials/Airbags/airbags.html
• https://consumerist.com/2014/10/27/maker-of-airbags-linked-to-8m-recalled-vehicles-used-unusual-chemical-explosive-for-inflation/
• http://www.theatlantic.com/technology/archive/2015/06/airbags/396854/