Fall 2009 Day 13

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Fall 2009-Day 14

Day 13 Topics

Moon Dance 3: Understanding the Moon's Shadow
Post Diagnostic Questions: Thermal Phenomena
Equal and Opposite Forces
Force Brainstorming

Peer Instructor Reflection

Fall 2009: Day 13
Written by: Katie Kizer

Class began with a trip to the roof! The moon was out and the sky was clear for once. We caught it! The students each pointed one of their arms at the sun and one of their arms at the moon. There was an angle greater than 45 degrees, but less than 90 degrees. This meant that the moon is in its crescent phase. It was lit on the left side, which also meant that the moon is waning (getting smaller). We had the students pull out their ping pong balls and hold them up so that they are making the same lit shape of the moon with their models. Half of the moon (their ping pong balls) was shaded. Why is half of the moon shaded? The students discussed this and talked amongst themselves. When we heard the right answer being mumbled, we asked them to repeat it. The moon is blocking itself. The back half of the moon is not receiving any sunlight because the moon casts its own shadow on itself. A common misconception is that the reason there is a shadow on the moon is because the earth is creating it. This is false information. We know this to be true because nowhere on the ping pong balls were the students’ shadows. Therefore, the moon must be causing its own shadow!

Back in the classroom, the students wrote in their notebook sheets what they had done and what they had learned. Soon after, Adam distributed the second diagnostic question about thermal phenomena. The students were asked to use their notes and all of the information they learned over the past few classes to answer the question and explain in detail what they know. Once they had finished this, there was discussion about everything that they had learned about thermal phenomena. Students went over their powerful ideas, and gave comments or asked questions that they were still unsure about. This led to other questioning about the moon and what is expected for the moon paper that the students are beginning to write for homework.

The next unit we will be working with is force! Emily had all eight students stand in a line and link elbows in the middle of the room. She had the four students on the left, pull to the left, and the four students on the right, pull right. The forces from both sides were equal. One way to demonstrate this quantitatively is to use two scales and have them be pulled in opposite directions. The force exerted by pulling in one direction must be pulled equally in the other direction or else the scales won't stay in the same place. Emily also had the students discuss in pairs what they knew about force and experiences they've had dealing with force. Instead of writing/drawing/presenting these ideas on a giant white piece of paper with markers like usual, she just had the students share with each other these ideas. Students took turns writing down words or concepts that deal with force that come from their background knowledge. They came up with: gravity, f=ma (force=mass x acceleration), weight, lbs, newton, etc. How do all of these words relate? I am excited to see what the students and the instructors will learn during this unit on force. It holds a lot of potential for fun learning activities!

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