- Some of the RECAST activities are set up more as demonstrations and other are hands-on activities for the students. Is there a benefit to one kind or the other?
- When I engage students in RECAST activities, occasionally some students see the outcome and are surprised by it, but instead of shifting their ideas, they "patch up" their old ideas instead of shifting to a new one. What is going on?
- Why do RECAST activites in ecosystems seem somewhat harder than those in density?
- I get the idea of how RECAST activities work, but I am having difficulty developing my own. How can I get started?
1. Some of the RECAST activities are set up more as demonstrations and others are hands-on activities for the students. Is there a benefit to one kind or the other?
In general, it is best to involve students in a hands-on way as much as possible, as long as you are also thoughtfully involving them in processing what is going on, but occasionally, there may be a reason not to. Typically, if you can secure enough materials for all students to engage with the activity, the outcome will be most convincing to the students. This is particularly so with activities where they need to "feel" the outcome, such as comparing the two cylinders of equal volume in density or the trying to draw liquid up the straw in the three flasks activity in air pressure. However, occasionally, there is good reason to decide not to have the students engage in such a hands-on way. For instance, in the two candles activity in density/sinking and floating, the outcome is more compelling if students assume that both liquids are water—their typical assumption—than if they are tipped off by the smell of the alcohol.
2. When I engage students in RECAST activities, occasionally some students see the outcome and are surprised by it, but instead of shifting their ideas, they "patch up" their old ideas instead of shifting to a new one. What is going on?
We have seen this, too, and it fits with the nature of human thinking. Shifting to a new model from one that has served you well for a long time can be difficult. This is particularly so when a model explains most of the evidence in the world. Why should one discrepancy be treated as evidence against the model? It could just be an exception. Until students have a chance to make connections to further test the new model and demonstrate it as being more powerful, it is a healthy response to be skeptical. Further, our everyday models often work in most instances and the exceptions are so few that we tend to discount them. It is how our reasoning works. We sum across instances in building models of the world.
3. Why do RECAST activities in ecosystems seem somewhat harder than those in density?
The teachers who have worked with us in density and ecosystems have also noticed this. For many of the physics topics, it is possible to develop activities and demonstrations that can easily be carried out in real time in the classroom. This is seldom the case for ecosystems concepts given that they often involve many individuals or population effects, emerge over time and across space. Therefore, many of the activities are in the form of simulation games or involve demonstrations that reveal themselves over an extended time frame. Computer simulations can address some of these difficulties. Chris Dede, who is well-known for his work in computer simulations and middle school learning, and the UC team have collaborated on an EcoMUVE to address some of these difficulties.
4. I get the idea of how RECAST activities work, but I am having difficulty developing my own. How can I get started?
The teachers that we worked with found it hard to develop their own RECAST activities right away. They needed to deeply understand the concept and what was making it difficult for students to learn. Then, if what was making it difficult to learn related to how they structured the concept causally, they needed to find a way to reveal information that would compel students to restructure their explanations. This is a lot when starting out. They found it most effective to get to know the examples well first and then to start to modify activities that they had used in the past that worked for some students but not others. This was how the condensation example on the site was developed. One teacher had put color in the glass but this was unconvincing to some students. By thinking about what was non-obvious to them, she was able to reveal the role of non-obvious water vapor in the air.
