A Chemistry Design Challenge

One of my favorite labs in chemistry class is the air bag lab. Students use vinegar and baking soda to produce carbon dioxide and fill up a Ziplock bag. This year, I set out make this a more STEMish lab by having students follow the Enginnering Design Process. In an effort to increase motivation, I also turned the lab into a competition. The winning team had to combine the correct amount of chemicals so that their bag would be as full as possible without busting. 

This activity requires a great deal of strategic thought from the students, as well as a thorough understanding of chemistry concepts. In order to be successful, students had to determine a way to measure the exact capacity of their bag, calculate the amount of chemicals needed to produce enough gas to fill the bag, and devise a strategy for keeping the chemicals separated until the bag is sealed in order to prevent gas loss.

One way that I differentiated the activity was by having hint cards that could be used for a small penalty. Students could request a hint card at any point in the process. The cards offered suggestions for how to measure the bag, how to carry out the calculations, and how to separate the chemicals while sealing the bag. The competetive nature of the activity caused students to save the hint cards as absolute last resorts. 

This proved to be a great culminating activity for my students. They had to have an in depth understanding of gas laws and stoichiometry in order to be successful. I'd love to hear about your favorite lab! Please share in the comment section.

The Engineering Design Process

What does a STEM lesson look like in the classroom? How can I take a lesson and make it STEMish? These are questions I have asked myself quite a bit lately. They are common questions for teachers new to STEM education.

One model for creating STEM lessons is using the Engineering Design Process. The idea is to guide students through a process of discovery.

Engineering Design Process

As I reflect on how to drive my teaching more towards this model, I find myself focusing on the Imagine stage of the process. As we try to deliver as much information as possible to our students, this is an area that is often neglected.

One of my goals has been to turn some of my traditional lesson plans into STEM lessons. I have found that if my students are Imagining, the rest of the cycle falls into place. By Imagining, I mean brainstorming, looking at models or pictures and making inferences, researching, or discovering something on their own.

A chemistry example of this could be in the teaching of periodic trends. Traditionally I have used a lecture to teach students what the trends on the periodic table are and what causes them. I have followed that up by having them graph these trends. In an effort to have my students Imagine, I reversed this strategy last semester. The only front loading I did for the students was to give them the definitions of atomic radius, ionization energy, and electronegativity. I then challenged them with discovering the trends by graphing them. In groups, they analyzed their graphs and brainstormed causes for the trends. Rather than lecturing, I followed up the activity with a discussion that reinforced what they had discovered. This activity required the same amount of time as my traditional lesson.

Once I decided what part of the process students could Imagine, the rest of my lesson fell into place. Did they build a space shuttle or solve the world's energy crisis? No. Not yet. They did, however, take control of their own learning. They created a model for understanding the periodic table that we can improve upon throughout the remainder of the course.