Wednesday, February 1, 2012

Oxidization happens

Who knew that cutting open some apples and potatoes qualified as a science lesson?

On Tuesday, the question was: If you cut open fruits and vegetables, do they have a chemical reaction with the gasses in the air? It is so interesting to me that most students intuitively hypothesize correctly, even when they don't have the science knowledge to understand why.

In the spirit of gradually releasing responsibility to students, after they recorded hypotheses, they read over the procedure and planned how to collect data on their own. We did do a quick check in on the procedure, and students had a chance to ask questions about issues that weren't clear to them. How many times will we do observations on the cut up fruit was a biggie, and showed me they were doing good planning for their observation charts. One savvy students wanted to know what the control was: the wrapped or unwrapped fruit. Kids were thinking.

So we cut up the produce, wrapped half of it in plastic wrap, and everyone wrote down what the two sets of food looked like. The student photographer of the week snapped a bunch of pictures as everyone worked.

Later in the day we checked back and most kids clearly saw that the exposed items had browned but the wrapped ones had not. Some groups chose to unwrap the plastic wrap and also felt the surfaces of the potatoes and apples and noted the wrapped ones were moister. One group felt like they needed to collect more data and chose to leave everything out overnight. This morning they did a final round of observations.

Before anyone wrote their conclusions, I reminded them to look back at the question to make sure their conclusion addressed the question, and didn't just state what happened to the fruit. I collected these and looked them over after school – I will touch base with the kids who did not write appropriate conclusions as a way to guide them in the right direction moving forward.

Of course, I squeezed in a three minute science lecture: one of the gasses in the air is oxygen, it reacts with the fruit when it is cut open and the cells are damaged, it is called oxidization and other examples of oxidization include metal rusting. Applying lemon juice to cut up fruit is one way to inhibit oxidization. Vocab connection: oxygen/oxidization.

Tuesday afternoon also is the day we go to the school's tech lab. This unit was planned collaboratively with our technology guru, Frank. (Also with our art teacher, Vera. More on that another day.) Part of our work Tuesday was to look at projections of the pictures our student photographer had taken and discuss which pictures could be used in a lab report/presentation. Kids taking pictures makes for a mixed bag on the iPad; hopefully our exercise got them thinking about how important it is to plan ahead for getting a picture at the “right” time in an experiment and how to compose a decent picture. Clearly this is something I need to keep working on; I missed the opportunity to get a picture of the lemonade fizzing!

Which of the pictures above do you think we decided would have a place in a lab report?

1 comment:

  1. Your lesson sounds like it brings out the best in your students. And your students sound like they have a lot of bests to let out. These blog posts are a gentle reminder to make more room for planning in my day.

    Thanks Liz.