Building Evidence: Yeast is a Living Organism

The claim that Yeast is a living organism started the process of investigation. My budding scientists have been thrown into the evidence machine and are working like crazy to collect evidence (the fun part), discuss it (the hard part) and evaluate how the evidence can be used to support the claim (the teeth-pulling part). The week began with students returning to characteristics of life and determining what evidence they had from the first experimentation. Large whiteboards served as the platform for this session:


Groups ranked the strength of their evidence: (+) if they believed it to be strong, (-) for weak evidence and (0) for no evidence. Many groups were unsure at this point of whether or not they had strong or weak evidence and few students seemed willing to go out on a limb and support their thoughts. This is new to them…

During this process I tried a new technique of shuffling groups and it turned out to be effective. Group members counted off so that each was a 1, 2 or 3. Then, during the analysis phase, a card containing a number was pulled and the student with that number rotated to the next table. Later on as we continued processing information, this process was repeated. In both instances, new insight was brought into the group and by the end new groups were also formed.

The new groups then focused on two characteristics: responding to a stimuli and being an energy user. Their task was to determine how to design an investigation (based off of the initial day of of experimentation) to collect evidence. We haven’t kicked around official terms for variables but most were getting the idea of controls and manipulating variables. A few surprises popped up. Groups investigating energy decided to experiment with sugar, no sugar and in a few instances, salt. The inflated balloon has sugar, the other was without or with salt.


At the end of the week, a few groups began processing this information. My goal is to bring out the idea of a scientific community between the four classes. I want students to share information throughout the classes. We’ll try a combination of poster and tech-infused ways to share data. This time, I asked students to create a poster that included a quick visual of the set-up (different colors for the manipulated and controlled variables), key observations, and an explanation of how their evidence supported or refuted their claim.

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