Students can explain the Big Bang theory and how it relates the Expanding Universe theory.
Students can list the basic tenets of the Big Bang theory; student exit tickets demonstrate knowledge of the theory and list relevant questions.
Students can explain and clearly illustrate the Doppler Effect.
Student illustrations and accompanying explanations show a correct interpretation of the Doppler Effect.
Students can evaluate how observations of red-shift in stars and the Doppler Effect support the Expanding Universe theory.
Student illustrations and accompanying explanations correctly and clearly connect the tenets of the Doppler Effect to the Expanding Universe theory.
Standards: AAAS Benchmark 4A: The universe contains billions of galaxies.
ISBE Standard F: Sun compared with other stars and galaxies.
Relationship to Driving Question: The theme of the entire unit is “our place in space.” In order to understand the Earth’s place in space, one must understand the scope of the universe. In order to fully grasp the Expanding Universe theory, students must also be taught some information on the Big Bang theory and the Doppler Effect.
Prior Knowledge: Students have likely heard of the Big Bang theory, but might not understand what the theory actually states. Some students might have heard about the expanding universe, but do not know the evidence used to support this theory. The Doppler Effect is likely new information; students should have some knowledge on waves and frequency that can be used as a foundation for teaching the Doppler Effect.
Instructional Strategies: The lesson consists of two major segments. Each segment will begin with a “phenomenon first” demonstration. These demonstrations will lead into whole-class discussions and a brief accompanying lecture. Students will then use the knowledge gained through these experiences to synthesize a visual product that explains the Doppler Effect and how it relates to the Expanding Universe Theory.
Instructional Resources: Expanding Universe demonstration is based on an illustration found in National Geographic: Astronomy textbook. Doppler Effect demo is based on a lesson taught in my high school physics class. Thanks, Mr. Piner!
Materials/Setup Needed: The Expanding Universe demo requires a large amount of bread dough containing raisins. This dough should be kept in the refrigerator until right before class begins to prevent premature rising. Immediately before class, the dough should be divided into fist-size sections, one per small group of students, and placed on a plate or paper towel.
The Doppler Effect demo requires a Doppler Effect demo ball: a ball, usually made of foam material, containing a sound device inside which emits a constant pitch when turned on.
Time Required: This lesson will require approximately two one-hour class periods.
Cautions: Instruct students not to eat the dough. Although the demo ball is soft, throw it softly and only to students who are prepared to catch it.
Instructional Sequence: Day One: Expanding Universe
Introducing the Lesson: Lesson will be briefly described to prepare students for demo. Instructions will not reveal how the demo connects with the space unit. Today, you guys will be split into small groups and will record some observations about an object I place on your desk. Pay close attention to the size and shape of the object. You may use a ruler to take measurements. Remember to take organized notes. Do we have any questions before we begin? Body of the Lesson: Begin by splitting students into small groups (no more than 2-3 students). Each group will be given a small portion of dough containing raisins. Groups will be instructed to watch the dough for several minutes (as long as it takes for a noticeable change in dough size to occur) and record their observations. A whole group discussion will then take place. Students will be asked to report what they observed. Teacher will ask guiding questions: What happened to the space between the raisins? Did the raisins change in size? How did the raisins get pushed farther apart? How do you think this connects to the space unit? After the discussion, the teacher will give students a brief lecture, with accompanying PowerPoint. This lecture will define the Expanding Universe theory, reveal the analogy to the bread dough demo, and introduce the Big Bang theory.
Wrapping Up the Lesson: Students will have to write down three things they learned from the lesson that day and at least one thing that they are confused about or would like to learn more about. This will be their “exit-ticket.” If time allows, a class discussion based on the exit-tickets will take place. Facts learned will be written on one side of the board and confusing concepts will be placed on the other side. For confusing concepts, teachers will ask if any student is capable of explaining the concept to the confused student. Students will also be assigned to watch a video on the Doppler Effect for homework. (Flipped Assignment)
Day Two: Doppler Effect
Introducing the Lesson: Students will watch the video found here (http://www.youtube.com/watch?v=FhfnqboacV0) before attending class. Using the flipped classroom in this case is useful because the material in quite difficult; exposing students to material before, during, and after class will help students understand this difficult concept.
Lesson will be introduced by reviewing material from the previous day. Common questions from the exit ticket will be reviewed through discussion. Once again, students explaining concepts to other students will be encouraged. Teacher intervention will occur as necessary.
The question will then be posited to students: “How do we know the universe is expanding?”
Body of the Lesson: Teacher will stand in the front of the room and a student will stand in the back of the room. Teacher and student will toss the demo ball back and forth several times. Students will be asked to explain what they hear: a higher pitch as the ball approaches them, a lower pitch as it moves away. The can then be related to other examples, such as planes, trains, and sirens. To explain this phenomena, the teacher will give a PowerPoint lecture. The PowerPoint will explain the Doppler Shift, explain how this shift can apply to sight and sound, and finally explicate the red-shift of stars and how this supports the Expanding Universe theory. The PowerPoint will use video, audio, and text examples to show the material in a variety of ways. This is a tough concept for middle schoolers, so the lecture will be as simplified as possible and the teacher should encourage questions. After the lessons, students will be asked to create a labeled diagram to explain the Doppler Effect and red-shift of stars. On the back side of the drawing, students will be asked to write a brief paragraph that explains how the Doppler Effect supports the Expanding Universe theory.
Wrapping-Up the Lesson: After students finish their drawings, they will be encouraged to compare their work to their classmates’. Discrepancies between their drawings can reveal misunderstandings, allowing the teacher or other students to correct these issues. The drawings will be turned in to the teacher at the end of the class period. These drawings can then be observed by the teacher as a check for student understanding of the lesson. Drawings and explanations should both be accurate. If there are common inaccuracies, these can then be addressed.
Design Rationale: These lessons demonstrate phenomena before providing explanations because the concepts are quite difficult. If students can relate a simple, observable event to a complex idea, they are more likely to understand it. Adding the flipped element to the second demo lesson adds an extra element of this phenomena first idea. By being exposed to the phenomena before and during class, students are more likely to make connections and grasp the difficult concepts. To assess this learning, teachers need a work product from students. Students leave the teacher with a concrete product at the end of both classes that can be used to assess student understanding. Based on these products, the teacher can correct misconceptions or clarify concepts if necessary.