Doing More Reflection!

Reading!

I looked back and noticed I had avoided reflection in two of my blogs (on questions 2 and 4). To bolster those weaker blogs, let me offer one extra reflection today (and I will catch up the other one next week). One strategy for me to better understand the students and their prior knowledge and interests is to share my interest in literature. I love reading, including young adult fiction that involves dystopic societies or Gary Paulson. I noticed that my cooperating teacher makes comments about the books her students have out, and I make comments when I see that the high schoolers are reading books that I love. Now, the high schoolers sometimes draw me into what they're reading ("Sally, have you read The Book Thief? Have you read Divergent?"), and it's a way for me to relate to them and know what examples and interest-grabbers I can use (I couldn't call my students erudite 5 years ago!). Also, it makes me a better model as someone who is interested in science but has a life outside of school; it's okay to be a scientist and have other interests. 

Dry Ice Investigation

I taught Mr. M's physical science class today. They have been studying chemical and physical changes, the different phases of matter, and phase changes (basically, chapters 2-3 of Pearson's Physical Science book). This investigation I did with them developed through a couple iterations at Chemists in the Library, and the original idea came from the kids section of the ACS webpage (https://www.acs.org/content/acs/en/education/whatischemistry/scienceforkids/chemicalphysicalchange.html). 

Procedure

I had the students do an investigation with dry ice in which groups of students worked in groups to research dry ice online, make predictions about what would happen if they dropped dry ice in soapy or salty water, collect observations and measurements, and report and explain what they saw. They had to classify the phases and phase changes that they saw, as whether they were dealing with pure substances, homogeneous mixtures, or heterogeneous mixtures (my Minnesotan accent sounds really funny with all of these terms, but the students were polite). Besides making global observations and measurements, they also did dimensional analysis on individual bubbles. 

Results

They were also to explain the process of sublimation, although they didn't use the terminology. That is fine with me--they knew that they started out with a really cold solid that turned into a gas, and they knew the gas must be denser than air, because the vapors fell down to the benchtop. One misconception that I was glad came up was that there must be something in the bubbles, even if we can't see what it is--at first, some of the students asked if the bubbles were empty or if gas came in when the bubbles popped. They came up with all different temperatures for the water, which stumped them and was something I should have left time to discuss (now, I feel like I've sent them off with a new misconception). 

They got different volumes and surface areas (some students used the area equation) for the bubbles, which made sense to some of them and which they were able to explain. I also like that I didn't help them out too much when they asked me what equations to use; the hard part was not being able to look up "geometry" on Wikipedia but in figuring out how to make measurements on bubbles when they were quickly popping. 

Things I Could do Better on this Investigation

Of course, although I tried finding a two minute video this week on dry ice as an anticipatory set, once I finished my prelab talk and set the students off to do research, they found much better videos than I ever could. I knew the students would be more interesting and creative than myself, and I will use the videos they showed me the next time I teach physical changes. I could have also prepared a pre-assessment, so I would know exactly what they thought about whether or not bubbles are empty or having something inside, whether sudsy water is homogeneous or heterogeneous, what they know about dry ice, and what they know about finding the surface area or volume of a shape. 

Before letting them loose, I should start off teaching them how to read a thermometer, because it's silly that I assumed they all knew how to do so. I'd also like to spend more time on the dimensional analysis portion (find the surface area and volume of the whole pile of bubbles coming off of the dry ice) and to address the misconception I set up on different temperature readings. I'm used to doing the dry ice investigation with the small children through Chemists in the Library, so I feel my lesson was a little on the fluffy side. There was some dead time when I could have had the students doing more online research or more dimensional analysis. 

Another thing that I will do better next time is to get more dry ice; Hyvee only had one small block, but I had to add the same block to the soapy water and then to the salty water throughout the period. Getting more blocks means that I could set up different stations throughout the room, minimizing dead time. The substitute teacher said that it matters whether you add the dry ice to soap first and then to the salt or vice-versa, since the soap really promotes the opaque bubbles that are created in the soapy water. Interestingly, the thermometers only went down to -20 deg. C, which I thought was interesting in and of itself. If possible, I would use a variety of thermometers (some that went down past -78 deg. C, and maybe even some that stopped at zero) to see what discussion would arise from giving students more options on equipment to use. 

Lessons I Learned Today to Extend to Teaching in General

I decided today that one of my major classroom rules is going to be that students are not allowed to say things like, "You're the smart one, you do it" or "I'm bad at science/math." It makes me really angry when students make excuses like that to have their partners do their work (whether because they don't want to do work themselves or whether they already honestly believe that they are bad at science). It reminds me of my best friend's kid, who was okay at first making predictions but then became too nervous to make further predictions. 

The students possibly don't know that science is supposed to be difficult--it isn't just looking up pi*r^2 on the Internet (I am not setting them up with a good example, if I give them too easy of work to do!). Also, our culture allows for this kind of permissive attitude for not trying in science and for thinking that science is for special people. Neil de Grasse Tyson has been saying in Cosmos, our culture also promotes this kind of laissez-faire attitude towards science--the stereotype in American culture goes that only nerds do science and that it is okay to make excuses for not trying that we would never make in other subjects. 

I think I will just make up a poster with my four-letter words ("geek," "nerd," and "can't"). I used to tell my students that I'd cry a million tears if they did x, y, or z (e.g., forget to include units on appropriate data). I should revive that saying before I have my own classroom and can make that poster.... I will also give my students multiple chances for success, so that they know that they can do science.