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Matter and Motion
Broughal Middle School, Bethlehem Area School District
In-Service Program for Grade 6 Teachers, 25 November 2009 |
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Hello! Wednesday, November 25, 2009 was an In-Service day for teachers in the Bethlehem Area School District. This is a description of one of those programs. The sixth, seventh, and eighth grade science teachers met separately from those in other fields. We met together for about an hour, before the 6th grade teachers separated from the others. During this first hour, Dr. Alec Bodzin from Lehigh University engaged teachers in a discussion of inquiry-based learning methods. That's Dr. Bodzin on the left. And, below are some of the teachers who interacted with Dr. Bodzin during this part of the program.
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The remainder of this description pertains to the adventures of the sixth grade teachers. They worked with Dr. Gary DeLeo, a Professor of Physics from Lehigh University, and one of Dr. Bodzin's graduate students, Mr. Ali Shameem. With Dr. DeLeo's assistance, the teachers - Mr. Matt Lyons and Mr. Barry Schultz - worked on programs involving matter, including both physical and chemical changes, and motion. We began with physical changes. We know that when the temperature is lower, the atoms move more slowly. So in a solid, such as ice, the atoms move slowly and stick tightly together. If you take an ice cube out of the freezer and let it warm up, the atoms begin to move more quickly. They are still close together, but now they can move enough to roll over one another, and we have a liquid. If you place the water in a pan on the stove and make it real hot, the atoms become unstuck and zip all around the kitchen. Now, you have steam, which is a gas.
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We began by considering an experiment where students would monitor the temperature of ice as it made a transition from solid to liquid. An important feature of such phase transitions is called latent heat. As energy goes into the ice from the room (or a hot plate), it raises the temperature of the ice until it reaches the freezing point. At that point, the temperature stops rising. Now energy goes into changing ice at 32 F into water at 32 F. This energy is called the latent heat of fusion. So, if we monitor the temperature, we should see it rise until it reaches the freezing point. And then it should remain flat until the ice turns to water, at which point it will rise again.
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| In order to ensure that the ice was well below the freezing point, Dr. DeLeo used liquid nitrogen to cool it further. We used temperature probes and a computer to record the temperature as a function of time. The red trace on the lower right shows the flattening of the temperature graph as the freezing point was reached. If we allowed the ice to melt, the curve would continue to rise again. |
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In the next part of the program, we considered an activity involving chemical changes. Each student will perform a set of chemical reactions in a Ziploc bag, the kind with the tab. The clear bag allows students to see the color changes, observe the production of carbon dioxide gas as the bag inflates, and feel the temperature changes.
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| As shown in the photo sequence, calcium chloride is first placed in the bag, and this is followed by univeral indicator. The use of universal indicator instead of water simply adds a color change to the reaction. When Mr. Lyons poured in the univeral indicator, not only did the color change, but, as you can see from Mr. Schultz's expression, the bag got very hot. This is an exothermic reaction - it gives off energy. |
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| In the next step, baking soda was added to the bag. This time, there was another color change, the bag got very cold - an endothermic reaction - and the bag inflated with carbon dioxide gas. Don't we look like we're having fun! |
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Here is a video showing the entire activity, run by Mr. Lyons and Mr. Schultz. Just click the play button on the photo on the right.
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In the final part of the program, we used a Pasco Motion Detector and software to record position, speed, and acceleration for three different types of motion: cart rolling down an incline (like a falling object), cart on a spring, and a person walking. The walking part is called "walking the graph." Here, one draws on the board a graph of position versus time, and asks a student to walk in such a manner that the graph is reproduced by the motion detector and software.
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| The video on the right shows the activity involving the cart on a spring. The video on the far right shows Mr. Schultz working the computer while Mr. Lyons walks the graph. |
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Although Dr. DeLeo seems to avoid appearing in any of the photos, he was all smiles for the full five and one half hours of the program! He had a wonderful experience working with the teachers at Broughal Middle School!
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Although we have endeavored to exclude photographs where permission has been denied, it is possible for errors to occur. If you would like us to remove a photograph of your son or daughter for any reason, please send me an e-mail message at lgd0@lehigh.edu or call me at 610-758-3413, and we will remove it promptly. Please note that we will never associate a child's full or last name with a photograph except in circumstances where special permission was explicitly provided. Thank you. Gary DeLeo. |
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