Molecules in a Solid (Day 1)
Lesson 4 of 8
Objective: SWBAT model the effect that thermal energy has on solids, liquids and gases.
According to the AAAS, 32% of students polled in a study by Musonda (1991) think that solid molecules are not moving. I want to get my kids thinking about solids and identify any alternative conceptions that may interfere with their conceptual understanding of matter and motion. I ask them:
"Do the molecules of a solid move? Explain."
I give them a few minutes to jot their responses into their science notebooks. We then review as a class. I explicitly state that it is not a matter of having the right answer, it is about sharing our ideas and then finding answers. My students know that this is a safe place to share ideas and thoughts, and that it is unacceptable to make fun of students' ideas. I record their thoughts on the board and we revisit them at the end of class to gauge understanding.
Introduction to Lesson
KLEW charts, or KLEWS as it is in this lesson, is a modified KWL chart that incorporates the use of evidence, wondering, scientific principles to support learning. This strategy supplies students with the structure required to participate in their own inquiry investigations.
This lesson has students investigate the role of expansion joints in bridges and other devices to demonstrate that solids move, just like liquids. Through the course of investigating various images, links and videos, students will see how our understanding of matter can be applied to keep people safe.
After introducing how a KLEWS chart works by going over each column, I explain to students that they will be using their Chromebooks to participate in 3 different activities:
Part 1: Students will then open part 1 and record all important and useful information in their KLEWS Chart (Primarily Columns 2, 3 and 4).
Part 2: Students will then record observations from the picture in this part and then address the question, "Why do sidewalks and bridges have expansion joints?" at the end. They can then address the answer to that question in the S column of the KLEWS chart.
Part 3: Now that students have a better understanding of solid molecules moving at different temperatures, I have them research a place that uses expansion joints. They must, then, model their understanding of why they are used at that location.
Wrap-up: I then take a poll of how many students think that molecules are moving and the evidence that they have to support that claim. I ask, "Do the molecules of a solid move?"
Student-centered learning occurs when teachers provide the necessary structure and strategies for student success. This lesson provides students with the necessary structure to record what they're learning supported with evidence using a KLEWS chart. NGSS Science and Engineering Practices 6 (constructing explanations) and 7 (engaging in argument from evidence) are stressed in this lesson, as a way to help students determine if molecular motion responds to temperature changes. There is potential to tie in patterns (crosscutting concept) by having kids compare and contrast the ways the solids, liquids and gas respond to temperature changes. This will be the do now in tomorow's lesson to help assess student learning and help my students apply what they have learned. I hope that they can see a pattern that, regardless of the state, all matter expands when it is heated and contracts when it is cooled.
I explain to the class that we are going to the computer lab to research the essential question about how our knowledge of molecular motion can be applied to making safer bridges and buildings. Using the KLEWS chart, they will identify things that they're learning in column 2 and support how they know that with evidence in column 3. Any questions that they might be wondering about can be recorded in column 4. Column 5 is designated for recording scientific principles (Content) and crosscutting concepts--in this case, cause and effect and patterns.
I first begin by asking students to fill in column 1 (What I know) in their KLEWS chart with everything that they know about molecular motion, based on our previous lessons and experiments (2 minutes).
We then head over to the computer lab to research our question and students fill in their KLEWS chart. I stress the importance of pausing their videos, discussing with their group what they just learned and the evidence to support that, and how they should record that information in their chart. If they come across something that they don't quite understand--like in video 2--they can write down what they are wondering about it in the W column.
Part 2: Observing Images
Now that students have collected information about how thermal energy affects molecular motion, I want them to think more critically by applying their knowledge to explain real-life examples. I have created this document to help with this process. Students should complete Solids, Bridge and Sidewalk Pictures activity and record their answers in the science column of the KLEWS chart.
I want students to make connections that we can take what we know about science and apply it to solving everyday issues, like building bridges or buildings. We cannot ignore the scientific principles of nature.
We then review their responses as a wrap-up at the end of class. Again, if students bring up questions that we don't have time to answer, they can record them in the wondering section.
We then review as a class, allowing me to gauge understanding and plan meaningful remediation the next day. I also ask, by a show of hands, how many students think that the molecules of a solid move. This ties in the do now from the beginning of class and is another source of data to gauge understanding of the molecular motion of solids.
I mainly want to hear students correctly using the words expansion, contraction, molecular motion, thermal energy, increase, decrease, as well as explaining the cause and effect relationship of heat and molecular motion correctly, as well.
On day 2 of this lesson, students will pick a specific location on earth where expansion joints have been used to demonstrate deeper understanding of molecular motion and thermal expansion.