Discourse Tools

Working with science ideas

Throughout the unit the students are working on developing a model of the interrelationships of fungi processes. Each activity layers on more background information so that by the end on the unit students are able to construct a model showing the interrelationships of digestion, respirations and reproduction in order to explain what decomposers do and how they use the energy harnessed by these processes. To better understand digestion and respiration in yeast, students construct and modify a digestion-respiration model. After learning about digestion students do one round of yeast investigations in which they make inferences about observations such as the production of gas. The design a model based on their observations. Then after learning about respiration students engage in more open-ended inquiries to better understand both digestion and respiration. They use information from the yeast experiment and texts to modify their model. Janet scaffolds the students’ use of science concepts in written explanations by having students construct concept maps as pre-writing assignments. Students first do a concept map with ideas related to extracellular digestion and later do another with terms related to decomposition, digestion, respiration and reproduction. Students use both of the maps to write an explanation for why strawberries rot over time. She not only scaffolds students’ use of science ideas but she asks students to participate in model-building as a scientific endeavor. In terms of “thinking like a scientist,” Janet also helps her students use evidence-based explanations. During the yeast investigation she constantly presses students to connect what they are seeing to what unobservable processes might be taking place.

Scientific Method focus
Teacher asks students to identify variables and describe the experimental set-up. Science concepts are played down to afford time to talk about designing experiments. Talk with students is about error and validity.

Discovering or Confirming Science Ideas
Teacher has students discovering science concepts for themselves (without much background ahead of time) OR Teacher has students use an activity as a “proof of concept.” Does not include hypothesizing about these observations and descriptions.

Hypothesizing about observations and descriptions
Teacher asks students to predict what they will observe happen in the investigation. Focus is on describing how variables change outcomes.

Forwarding science ideas to work on
Teacher foregrounds key science concepts and asks students to use an investigation to make sense of the concepts. Focus is on sense making between data and developing science concepts.

Epistemic Fluency/ MBI focus
Teacher set up for inquiry and data collection is purposeful and highlights tentative explanatory models as the basis for investigation and data collection. Teacher uses model as a touching point before, during and after an inquiry and strategically builds in background knowledge of key scienceideas and models before, during and following an inquiry.

In this way, Janet moves beyond just asking students to describe what variables they are manipulating and beyond just giving students background information to help students focus on unobservables during the investigation but rather her focus is on model-based inquiry and teaching students about the nature of scientific work.

See the continuum above for a range of how to engage students in scientific practice, from least effective (Scientific Method focus) to most effective (Model-based Inquiry—MBI focus).