Welcome to Day 3 of our three day exploration of bioengineering and microfluidic chips!
Day 1 starts with an introduction to the field of bioengineering and specifically the use of microfluidic chips.
Standards: W.9-10.2, W.9-10.2d, SL.9-10.1
During Day 2, students will design and fabricate their own microfluidic chip design.
Standards: SL.9-10.1, RST.9-10.3, SP3, SP6, SP8
And today, students wil use their chips to observe laminar flow and reflect upon the engineering design process.
Standards: SL.9-10.1, W.9-10.2d, RST.9-10.3, SP3, SP6, SP8
Today is the most unpredictable of the three days of lessons…and that is ok! Some chips will work while others might break when students take them off their plates and turn them over in order to use them. Some years I have made extra chips and others I haven't and in either case, students have continued to be engaged and involved in the work of other groups either as partners or observers no matter what happens with their own chips. In fact, when I have not had spare chips available, students typically are motivated enough to ask if they can redo their design and retest it on their own time the following day!
The energy in the room will be high and students will be intensely involved in the physical nature of what they need to do--it takes concentration and focus!
I have worked with this lesson for a few years now and I am also most nervous on this day because I, too, do not know how it will all turn out…which is a big part of the engineering process. So far, it has always turned out to be a good experience no matter what happens.
1. Ask students to take out their engineering design notebooks and open to the data collection page for the day.
2. Introduce today's work: to take chips out of their molds and get fluid flowing through them! Due to the open ended nature of the lab session and the novelty of the topic we are studying, I spend some time in a directed teaching mode here and you can see it with my notes in the following Classroom Video: Expert Review, Work Plan and Focus.
Here is the process, which you can write on the board:
a. Students will take their chips out of their molds and place them with the channels down onto another plate or flat surface.
b Students can use a straw to poke holes in each of the three ends of their Y channels.
c. Students will use colored water and syringes to show the laminar flow phenomenon within the fluidic chamber as demonstrated below in this student video.
d. Other student groups will be using pH paper to demonstrate the interaction of fluids with indicators within the channels.
1. Ask students to move to their lab tables and begin working with their chips. They will be hesitant to get started by removing their gelatin chip from the mold they created yesterday. I encourage you to feel comfortable keeping your instructions to a minimum, encouraging them to consider a logical plan and support the idea that there are multiple ways to get the chip out of their mold. You can see one simple way to get your students unstuck while still allowing them to experience the iterative engineering design process in the following video clip Classroom Review: Wait Time.
2. Students will be productive, focused, and collaborative throughout the class period and I encourage them to share their work with each other informally with groups/pairs moving around the room to compare and comment on each other's chips and the laminar flow demonstration. You can see one way I use our small group conversations to deepen the student experience in the following video Classroom Video: Rephrasing.
A video of this process will help you show students what they are trying to do in this step.
1. At the end of the session, bring the class back together as a large group and lead a discussion in which each lab group can share out their work following our spokesperson protocol which you can see in action in the following Classroom Video: Large Group Share Out . Use the following prompt to assist students in shaping their comments to share:
Challenges? Surprises? Successes? Observations?
2. As a last step, ask each group to think of two tips or tricks they would want to share with other students doing this lab and choose a spokesperson to put them up on the board for the rest of the day's classes to view. Invite the spokesperson from each group up to the board to write up their group's tip. I keep this list posted up for the rest of the day so that students can compare how the experience went for each class period. Students enjoy reading each others addition to our board and it can serve as a support for your planning throughout the day and into next year's version of the lab. Take a look at this short video Classroom Video: Spokesperson Protocol to see this thinking wall version of the spokesperson protocol.
3. If there is additional time after this activity, students can then fill out the rest of their engineering design notebook and their bioengineering student feedback sheet. If not, direct students to complete this feedback and planning document at home.