I couldn't resist opening up the lesson today with a review on our vocabulary word: chemical reactions. A picture is worth a thousand words. Everyone loves this video!
Of course the laughter was rampant and the noise level was out of control before the video was over. Students wanted to watch it again, but alas, we needed to get to the lab and get going on the second day of our Mystery Powders!
Today was Day 2 of our Mystery Powder Lab! Students entered the lab with their Observation Chart and pencils. I opened the lesson with an introduction to Day 2 that reminded them about what yesterday was about. This helped them get focused on what was next. All of the lab testing sheets had been left in place on the counters around the room. I had vinegar prepared in paper cups, eyedroppers and paper towels ready for them to get. The "Gophers" would get the necessary supplies after they made their observations of the evaporation test.
I asked students where they remembered they needed to start today. Hands shot up and students recalled that the evaporation test needed to be looked at. Some students hadn't gotten to the evaporation test, so those students would start with the water.
They broke into their groups taking their observation sheets with them. I reminded them that the same team protocol, safety procedures and precise language use in their observations were to be practiced.
As students got to their stations, I asked several questions as they were observing their evaporation tests. Many touched the powders in the Day 2 Observations to find stickiness or hardness on their sample sheets. They noted their findings with precise words. I coached them to use precise words and compare the indicator test to every powder they use.
When groups were finished noting their observations, they were ready to start the vinegar test. It was great when I heard the reactions to the Vinegar Test. Some did not have the fizzing when the vinegar mixed with the baking soda. "It's like really soggy" was one explanation of what was going on. "And bubbles started coming" caught my ear as students explained what was going on on their sheet. The lab continued as they wrote down their observations about color and descriptions of the reactions. Students enjoyed this part of this lab because the vinegar also turned the cornstarch a color. It gave them opportunities to use different descriptive words.
I could see students were finished, so I had them return their vinegar to the center counter and prepare for a little discussion. They finished up their observation sheets.
I asked students to share some of their observations from today as we finished up our lab. They shared words like "bubbling," "fizzing" and "turned a golden color." There were no students who shared any vague words. I was seeing progress and avoidance of words that weren't precise. I am thinking they are understanding completely what words we should be using to describe science!
I told students that tomorrow would be "Mystery Powder Day." I told them we would be using iodine in our experiment for our last test and then we would apply water, vinegar & iodine to the mystery powder. I asked them to predict which powder they thought would react to the iodine?
Most students said that they thought the baking soda would react because it did today. This question was purely to set the stage for thinking and I wasn't looking for accurate reasoning because they don't understand the chemical properties. For example, they don't know that when corn starch comes in contact with iodine, it turns a greenish color.