Microscale and the Perfect Storm

"What are we doing to help kids achieve?"

Lately, it has been the perfect storm of difficulties. There have been the difficulties of short classes, little lab time, material becoming more difficult and the overall struggles of winter and trying to get through concepts. These struggles were in the back of my mind as I was trying to plan out the progression of lessons and concepts for the next few weeks. The progression our department uses at this point is typically percent composition, hydrates, empirical and molecular formulas, balancing and types of reactions. My mind was spinning as I was trying to figure out how to get through this in a reasonable time frame. Good news appeared in my email. I learned that the microscale book by Bob Worley appeared in my in box. I was going to hold off and wait to use it. I had used bits and pieces of Bob's ideas that I had liberally stolen from conferences and email correspondence. I knew that if I sat down with this book, hours later I would be still reading it. It was one of those books that I wanted to selfishly hang onto for summer reading. But something got the better of me...why not just take a peek? That is when the flood gates opened. I thought I could just do one experiment on a whim. I started with the hydrate experiment with the kids. The video link shows a short quick version. It was quick, fast, easy, and the students were able to complete multiple runs during a shortened bell. I was able to talk to Bob and he mentioned that I should probably pull back a bit on the amount of hydrate used. Students could also use two bottle caps. One could act as a lid. All good ideas to try for next year.

Video 1: Determination of empirical formula of magnesium oxide, Chad Husting YouTube Channel, February 23, 2022.

Next came empirical formulas. Again, I saw an experiment that I had never seen before. Students use the bottle cap method to have magnesium go to magnesium oxide. See video 1 above. Each student group did one trial and we collected data over multiple classes. Students then were provided with three possible formulas and balanced equations for the formation of magnesium oxide. Only one was correct. We worked as a class to determine which would be the best. This method included graphing, error analysis and an introduction to balanced equations. Overall, this was a good lab. Some of the bottle caps reacted with the magnesium but I think I have that part figured out for next year.

Video 2: Single displacement reaction, Chad Husting YouTube Channel, March 3, 2022.

Then came balancing and types of reactions. I now had the pdf version of the book on my computer. There was a single displacement reaction that again I had never seen and I had talked to Bob about this. Essentially, you can pass hydrogen gas over a small glass tube of some copper (II) oxide and it goes to water vapor which appears on the glass and pure copper metal. You only need to heat the copper (II) oxide with an alcohol burner for a few minutes. I also had attended Dr. Bruce Mattson's workshop awhile back on microscale gases (see the link here). I was able to quickly and easily make some hydrogen gas and pass it over the warm copper (II) oxide. Usually, nothing ever goes well the first try but this was a total winner of an experiment (see the video 2 above here). Not only could we demonstrate the single displacement reaction of the hydrogen gas and copper(II)oxide but also the magnesium and hydrochloric acid to make hydrogen gas for use in the experiment.

Going back to the book, there are some nice experiments on "puddle" chemistry that tie in nicely with types of reaction. I had attempted this in the past. It was extremely helpful to have the concrete examples in the book. We typically start with a "problem of the day" in chemistry but I started doing "experiment of the day" with puddle chemistry. Students would quickly do a "puddle chemistry" experiment at their lab stations. Next we would return to our seats to discuss and try to predict results. Finally, they would return to the lab stations to check their reactions and see if the predictions occurred. Quick, fast, simple and clean up involves a paper towel. I could spend ten minutes on prep and have enough ready for six classes. Below is a picture of students reacting magnesium and iron(III) chloride. I especially like this reaction. They can watch the dissociation and dissolving of the iron(III)chloride. Many students really do not understand the process of dissolving and this provides some great talking points. Students also were stunned to find something unexpected, the iron, sticking to a magnet.

micro_puddle_mg_ironchloride.jpg

If we are talking about chemical reactions, then we also start talking about reactivity series. The microscale book has many wonderful experiments I hope to try. One in particular that I did with students was testing multiple metals in a petri dish on a piece of filter paper with small amount of sodium sulfate solutions and a multimeter. Essentially, each group has a dish with the paper in the dish and strip of magnesium in the middle. They are told this is the most reactive of the metals. Around the magnesium are different metals such as lead, aluminum, copper, iron and zinc. Students find the potential difference in volts between the magnesium and other metals (check out the video at this link). This quickly lead to great discussions on multiple concepts.  How are batteries made? Which metals are the most reactive? What is a sacrificial anode?

Video 3: Reactivity series investigation, Chad Husting YouTube Channel, March 8, 2022.

I finally found a type of rhythm that is starting to work for my students given the constraints and context of our post covid situation. Thanks to microscale experiments, I am able to get science back into their hands. I have let go of the idea that every experiment has to be a full blown lab or always has to be graded.

Something else happened...I am now on TikTok. Let me explain....

I wanted to be on another social media platform like I wanted a hole in my head. I am an older balding grey haired science teacher with a speech impediment who makes terrible videos. My students have told me multiple times that I have the perfect face for podcasting...and I believe them. But they also convinced me I should get on TikTok. So here was my thought...this is where most of my students live. Maybe I need to meet them where they live? At the end of the day, all I really care about is if they are getting excited about science. So I jumped onto TikTok (if you are interested @0gochemistry on TikTok and @ChadHusting on twitter). A funny thing started happening. Students started working much harder on their microscale experiments. They wanted to know if I would put their experiment on my TikTok channel. Hmmmm...I wonder if there is an idea there?