By Julie Olson, Collaborative STEM Innovation Fellow and award-winning science teacher at Mitchell Senior High/Secondary High School, Chance,South Dakota
What started out as an idea for our Physic Photo Contest turned into a full- blown, very engaging STEAM learning experience for several at-risk science students.
The photo contest, in itself, is a great STEAM project in which students explain the science behind a natural or contrived photograph. Here’s how the project worked with my students: A student chose to photograph and explain the hydro dipping process using a plastic soda bottle. The basic hydro dipping process involves putting spray paint on the top of a tub of water, swirling it with a stick, then dipping an object into the water. Choosing the colors, the amount of stirring affect the process. As I wanted to capitalize on a teachable moment, I explained the science behind hydro dipping. That explanation prompted me to start thinking how I could make deep connections, excite my students about learning, and develop a great STEAM unit.
The next day, I discussed hydro dipping with some students who were not very excited about their Chemistry lesson. We talked about the basics of the process: a non-polar (molecules do not have a charge) substance such as paint is floating on water that is polar (molecules have a charge). The paint floats because of the density, and unlike substances, do not mix. Working together, we produced a couple of swirled plastic bottles. One student added to the conversation by noting that he had a motorcycle helmet “dipped” but with a skull design! The questions started flowing. How was that done? What did they use? The fire had been lit! We investigated and found that, in commercial processes, there are special paper and inks used to print designs. What was the cost? What kind of ink? What was the paper coated with? So, yes – more questions and thus ensuing investigations to do.
The lesson depended upon having printers available that used pigment-based inks instead of dye-based. The dye-based inks are water soluble and would bleed as well as focus the color. Pigment-based inks are water insoluble and reflect light. Photography uses pigment-based inks, while most ink-jet printers use the dye water-soluble inks. The paper was then coated in PVA (polyvinyl alcohol), which is a component of glue as well as hairspray. It is water soluble.
So, our investigation began as we had to find out how to create a PVA film and what to place it on. Just trying a variety of papers (e.g. wax, parchment, cardstock, foil, and plastic bags) and PVA sources (e.g. hair spray, white glue, and wood glue) was a great exploration into materials. We have now created some films and students have drawn preliminary designs on paper to later transfer it to the PVA film. But there are still intriguing questions to answer: How long does the film has to float on the water? How hot does it need to be? What is the fixative? These questions and subsequent investigations are fueling the students’ desire to learn as well as giving them a personal connection to that learning through the creation of a work of art. This is a STEAM lesson that other teachers could easily adapt for their own science and/or visual arts students. I know that it is a lesson that I will definitely repeat my students!