Tuesday, July 24, 2012

#ModChem Day 11

Modeler's Log, Day 11--

It was unusual how we had a sneak peek at today's workshop day, because we actually had to prepare for today's session a couple of days ahead of time. Due to the constraints of time in our workshop format, we had a multi-day lab that needed to be done for us so that we had the products at the start of unit 7. Since we meet for 8-hour sessions each day, it wasn't possible for us to do the lab all on one day, though we sometimes progress through more than one unit in a single workshop day. At any rate, day 11 has moved our particle model back in the direction of energy considerations, but not without a twist--

The day started off with a discussion of Gregg Swackhamer's Cognitive Resources for Understanding Energy. It is very challenging to put a summary of what he has to say about energy into words; however, the main points that we discussed dealt with:
  • The need to have a better way to represent energy in teaching science
  • There are not multiple "forms" of energy, there is only energy
  • Traditional approaches to teaching the energy concept result in circular reasoning or misconceptions of energy
  • Energy is not a substance, but it is substance like, and can be treated as being stored or transferred
  • The language used to talk about energy must not oversimplify nor mislead; it must be clear
  • Energy should be represented in multiple ways, not merely quantitatively through equations
Throughout the 40-page article, Swackhamer details many aspects of energy in various contexts and how to think about energy for understanding. Ultimately, we were all able to identify with the need to better teach energy concepts to students so that they have a conceptual model to apply in a variety of energy contexts.

Our paradigm lab in this unit is the Iron Nail in a solution of copper (ii) chloride. I wonder what will happen when this dark grey nail is submerged in this blue solution for a while???


We started by massing out the copper and iron before combining everything with water into a beaker. Then we combined everything in the beaker and made some observations. The beaker was left alone for a while and then the next day we removed the nail. Over time, the color of the solution and contents of the beaker changed. Once we removed the nails, we isolated all the "orange solid" that was in the beaker and had gathered on the nail. We washed this solid with water and acid, and then we put it on a hot plate to dry for a while. After all was said and done, we massed the nails again and the orange solid that had formed. The comparison was very interesting!

Upon speculation of what the orange solid could be, we reasoned that it was most likely solid copper metal. This led us to infer that copper and iron had switched places in the beaker, thus producing new substances that weren't there before. Specifically, based on our previously devised model of charged particles and ions, we decided that copper ions had become atoms on the surface of the nail where iron atoms had become ions and went into solution. After we whiteboarded our particle diagrams of this change, we concluded that the switching of places and changing of substances in the beaker amounted to what we wanted to call a "reaction," which is a term not previously used in our sequence. We defined a reaction as: a rearrangement of particles to form different substances.

We used our symbolic representations of elements and knowledge of how to write chemical formulas to represent what took place in the beaker. There we had it, a chemical equation for a reaction! One issue existed though, we weren't able to decide whether the iron in solution was in +2 or +3 ionic form, so we weren't sure how to balance the equation or predict the products. So, like good modeling students, we wrote out both possibilities on whiteboards and compared to our empirical data. The data showed that the ratio of iron to copper particles in the reaction was 1:1, and thus we were able to conclude the reaction that happened in the beaker:


The debriefing that led us to this reaction, the way to represent it with an equation, and a definition for chemical reaction took a fair amount of time, especially because we had a lengthy debate about the way to represent the ions in solution using our particle diagrams. Eventually, we arrived at consensus about what took place and how to represent it. Then, our day finished up with crafting whiteboards where we deployed our model of chemical reaction to represent the substances involved in a variety of reactions using particle diagrams. This would set us up for our next participant-led questioning session that will take place on day 12.

10 comments:

  1. The post is really superb. It’s varied accessory information that consists during a basic and necessary method. Thanks for sharing this text. The substance is genuinely do my dissertation composed. This web log is frequently sharing useful actualities. Keep sharing a lot of posts.

    ReplyDelete
  2. It’s difficult to get knowledgeable folks on this topic, but the truth is be understood as what happens you’re preaching about! Thanks. Find out who was born on any day in any month in history via our calendar of famous birthdays. Includes famous, historical, noteworthy and Celebrity birthdays.

    ReplyDelete
  3. Macroeconomics Homework the reliable help websites, we can say that assignment help is a reliable one. Their assignment writers across the globe are well trained in their chosen field of study which reflects in multiple offer. It is important to choose the best one among the many. Before choosing the one go for that website reviews first and then check the website like their services.

    ReplyDelete
  4. Search for materials on the Internet for personal statement writing. Active digitization of books, articles, dissertations and sources has led to the fact that for the lion's share of topics, "flagships" are easily searched for on the Internet. Even, for example, such a scourge of students-historians as sources on the Middle Ages has not been a scourge for five years now - enthusiasts have posted everything that can be found in Russian, plus they make new translations.

    ReplyDelete
  5. Hi. agree with you. this is a very interesting book. we discussed it with my colleagues from how to write an essay outline they wrote an article on it. and the author is very good! in general, my colleagues write gorgeous term papers and essays. feel free to contact them

    ReplyDelete
  6. There are lots of positive reviews from the Trustpilot and Sitejabber. So, it is also a service that is well-reviewed by customers write my paper for me cheap. Most students who have tried out the service admit in their reviews how quickly they got their essays (in a matter of hours). Besides, the experts are well-reviewed for their expertise in various subjects.

    ReplyDelete
  7. Hey visitors! Thanks so much for sharing such a fantastic information like this, as it siounds really awesome! But I need some help in study! Can somebody help me to write my papers online fast? Yes, this professional super writing help agency can. This company provides you the best literature review writing services. These authors have many experiences in this field of work. You can order assignments right now at their online page!

    ReplyDelete
  8. Sometimes it’s hard to fight to wean from habits, but it works out for me and all this is due to the fact that I get excellent grades because it helps write my essay for me cheap, according to which any written work is done, they help me

    ReplyDelete
  9. The student always dreams to pass the session with excellent marks, but this does not always work out because they ask a lot of essays. From a personal perspective, an essay for a student is a disaster! I know one site https://freepaperwriter.com/ which in such cases is always near the student and is ready to help him! It is very cool!

    ReplyDelete
  10. I want the teacher to appreciate the efforts of the written essay, I'm tired of writing them myself, so this site www.metrotimes.com/sponsored/want-to-buy-essay-online-top-10-trusted-writing-services-to-go-for-30728421 helps me, I go there when I need to buy an essay, there is also information about the 10 best reliable writing services

    ReplyDelete