Hot Potato Lab

This year, my school is teaching our high school Biology classes through College Board's Pre-AP program. Even my Honors Biology class is going through Pre-AP Biology. One of the concepts that I have to teach with this curriculum that I haven't before at this level is Surface Area to Volume ratio in the context of how it plays a role in the size of cells. 

I teach this in AP Biology and we do the Surface Area to Volume diffusion lab using agar with phenolphthalein and sodium hydroxide and soak different sized cubes in dilute hydrochloric acid. I love this lab, but don't want to do it with my honors bio students, since they would do it again in AP Bio. So of course, I did a google search and found this hot potato inquiry lab. 

From the lab linked above (which is the answer key to the lab), I put together a google doc for my students to work with. Here is the link to that lab document.

I loved this lab, and I'll be keeping it in my curriculum for sure. Like many of the labs I do with students, I was so busy helping them trouble shoot and prepare that I forgot to take pictures. 

My students liked this lab because they got to use our Vernier temperature probes, and they love to use the probes. Since they used probes, students could just poke the probe right into the potato. They could also see through graphing the data what was happening with the rate of temperature loss. (But maybe this made me more excited than them.)

Here are some tips for the lab. I forgot to bring a crockpot to keep the potatoes hot during the day and I didn't cook them ahead of time. I have an incubator in my room whose maximum temperature is 60°C. In the morning, I put them in the incubator. Right before this last block class I put the potatoes in my classroom microwave for 5 minutes to make sure they were cooked all the way (soft), then put them back into the incubator until students needed them. The key is that they start with the potatoes hot. Even just being in the 60°C incubator was enough to keep the potatoes warm enough for the lab. 

None of the potatoes started at the same temperature, but that didn't matter since we were looking at the rate of temperature change for each of the potatoes.  Students used Google Sheets to collect their data and then graphed a scatter plot, added trend lines and the equation of the trend line. We then discussed how the slope of the trend line is the rate of heat loss from each potato. 

Sentence Starters for Peer Review on Lab Reports

 I am currently in the middle of a  New Pre-AP Biology Teacher Cohort since my school is adopting the Pre-AP Biology curriculum for our Biology students next year. Today we were talking about the Pre-AP Course Framework and model lessons and how they support our teaching. Then we moved onto challenges that we may have that are not specifically addressed in the teacher supports. As we talked about the peer review that was happening for the student developed model of the carbon and water cycle in the lesson, we discussed of the struggle that students have in giving valuable feedback. One of our moderators suggested that we provide students with sentence starters to help guide them to more valuable feedback. 

This idea immediately resonated with me. After every mini poster presentation we do in class, students provide feedback to the other lab groups before I grade them. Sometimes students give great feedback, but often it is not helpful. For example, a favorite feedback of my students is suggesting that students write more neatly. Since I don't take points off for penmanship, this is not helpful feedback for improving their poster presentations. Usually toward the beginning of the class, after our first experience with peer feedback on these labs, I collect all of the feedback post-it notes and we work as a whole group to classify the feedback as helpful or not helpful. This leads to slightly improved feedback going forward, but still not as valuable as I'd like. 

This year I'm going to provide them with sentence starters to use.  I am debating about how I will provide them. One option is to project the sentence starters on the TV for them to choose as they are doing their peer review.  I could also print them, cut them out, and let students grab them to fill out instead of just giving them blank post-it notes. I've made Google Drawing that I can project, as well as pages of each sentence frame so I could print and students could fill them out. 

Here is the link for the sentence starters to project.

Here's the link for the sentence starters that could be printed and written on.