Today I did a demonstration lesson for my classes involving densities of different liquids. First period went great. The isopropyl alcohol, which I colored yellow, stayed sitting on top of the water, which I colored blue. Second period on the other hand, the two liquids mixed for an unknown reason and the whole solution turned green. The ice cube still floated in the middle, neither sinking nor staying on the very top, which was the expected result. Third period also gave the expected results, with the yellow isopropyl alcohol staying above the blue water.
I left the containers sitting on the counter in the classroom overnight, hoping that the one from second period will separate out. I must wait and see if the expected results happen. If not, the class and I will discuss some possible explanations and I will redo the demonstration so that they can see what I had expected them to see during the lesson.
My purpose for teaching this lesson was not necessarily the density aspect, as that is not my content standard. I was teaching the inquiry process and going step by step, thinking out loud, as a scientist does. Students made observations, predictions, hypothesized, made drawings and more predictions, wrote data in a chart, and tomorrow, we will finish the data results and the conclusions. Overall, I feel that the students really have a better understanding of the process. I had decided to do this lesson, even though it is already November, based upon my classroom observations during labs and realizing that they were missing big components of the process. They were unsure of how to create a hypothesis and then draw conclusions. I will add more after I see my final results from my second period class experiment. I really enjoyed the lesson, as I saw the expressions on my students' faces and heard the change in conversation throughout. This also happened to be my biannual observation, and my principal was very impressed with the level of understanding the students seemed to have gained from this lesson.
You remind me of the days when I taught 7th grade science. The last science class of the day was always the best because I had taught it 3 other times and had worked out the kinks.
ReplyDeleteShellee,
ReplyDeleteThat sounds like a fun experiment and a great way to get students "thinking out loud". We have a science standard for third grade in GA that even says that students should understand that similar investigations seldom produce exactly the same results and there can be unexplained differences. I'll have to look up that experiment and try it! Thanks for sharing!
Jessica,
ReplyDeleteIt was a fun lesson and the students were fully engaged in the learning process. And it was easy.
After repeating the experiment with my second period class using 91% isopropyl alcohol instead of 70%, for some reason, the liquids did not separate as expected. There was very minimal noticeable layering, unlike when I did the experiments for first and third periods. Those produced very distinct layering/separating of liquids. I'm still confused as to why I had differing results with this class.
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