Somnosurfin : What Do Waves Have To Do With Sleep? Student Information Page 3D

Transcription

1 Somnosurfin : What Do Waves Have To Do With Sleep? Student Information Page 3D Activity Introduction: Waves are involved in many natural processes, such as earthquakes, sound, and the movement of water in the ocean. Sleep involves the study waves also. In this activity, you will learn about waves and what they have to do with sleep. Activity Background: In order to study sleep, electrodes are placed on various parts of the body. During sleep, the electrical impulses produced by our bodies are recorded. These records turn out to have distinct patterns that closely mimic sine waves. (See Figure 1, Sine Wave). There are two characteristics that sleep scientists look at when analyzing these waves. They are interested in frequency of the waves and the amplitude of the wave. Frequency is a measure of how many complete waves pass a given point per second (or other unit of time). Amplitude is a measure of the energy of a wave. The amplitude is the distance from the crest (top point) to the axis. It is also the distance between the trough (lowest point) and the axis. Another important part of a wave is the wavelength, which is defined as the distance between two consecutive crests or the distance between two consecutive troughs. ENERGY + 0 one wavelength Figure 1 Sine Wave Activity Materials: (per group) Task Cards (these can be cut out and laminated to save paper and to make them reusable) 10 ft. nylon rope with electrical tape on each end Stopwatch Digital Cameras (if only one is available, it can be used by teacher or just one group) Computer Lab with computer for each group amplitude amplitude OBSERVER TIME axis Z Z Z ZZ 9

2 Activity Instructions: (Read each step carefully and check off when completed) Note: Either the teacher or a student selected from the class will use a digital camera to take a photo of the waves generated by one group every 5 seconds until a set of 30 pictures have been taken. p 1. The Reader will read each step out loud and be sure each group member understands and follows the directions. p 2. The Brain grasps one end of the nylon rope and wraps it with electrical tape and Receptor takes the other end and wraps it with electrical tape. Following all directions, they will generate a wave action in the rope. p 3. The Receptor will count every 5 seconds to help pace the Brain. p 4. The Observer needs to stand at the center of the rope so he or she can see a side view of the rope. Observer will direct group discussion and record group observations on the Student Data Page. OBSERVER BRAIN RECEPTOR READER Figure 2 Creating A Wave 10

3 p 5. p 6. p 7. p 8. p 9. When everyone is in place as shown in Figure 2 Creating a Wave, the Brain will move his or her hands as directed to start the wave along the rope. Creating Wave 1: The Brain will provide the energy needed to start the wave. He or she will move the rope by moving his or her wrist up and down. Take care to move only the wrist, not the elbow or shoulder. Keep the wrist movement going at a rate of five up-down movements every second. The Receptor holds his or her end of the rope as still as possible and at a constant height. The Observer watches what is happening to the rope and reads the questions on the Student Data Page, recording the group observations. If your group is providing photographs for the class, the photographer will take pictures as the Receptor holds the stopwatch and calls out every 5 seconds so the photographer can take a picture of the wave at 5 second intervals until 30 pictures have been taken. Creating Wave 2: Repeat the procedure, but this time, the Brain will initiate the wave along the rope by moving his or her elbow. Move the elbow at a rate of two up-down movements every second. Again, the Receptor holds his or her end of the rope as still as possible and at a constant height. p 10. Creating Wave 3: Repeat the procedure a third time, but this time the Brain will initiate the wave along the rope by moving his or her shoulder and keeping the arm straight and locked at the elbow. Move the arm at a rate of one up-down movement every second. The Receptor holds his or her end of the rope as still as possible and at a constant height. p 11. As a technology option for this activity, save the photographs taken of the waves and distribute to each group. The groups will then insert the photographs into Windows Movie Maker to create a movie of the three waves generated in this activity. Students can use the movie to more accurately observe the waves generated in this activity as they answer the questions on the Student Data Page. Z Z Z ZZ 11

4 Group Observations: WAVE Somnorifics : What Do Waves have to Do with Sleep? Student Data Page 3D 1. Describe the amplitude (height) of the waves generated when the Brain moved his or her wrist. 2. How close together were the crests (tops) of the waves generated when the Brain moved his or her wrist? 3. Generally, how would you describe the frequency of the waves created when the Brain moved his or her wrist? WAVE Describe the amplitude (height) of the waves generated when the Brain moved his or her elbow. 2. How close together were the crests (tops) of the waves generated when the Brain moved his or her elbow? 3. Generally, how would you describe the frequency of the waves created when the Brain moved his or her elbow? 12

5 WAVE 3 1. Describe the amplitude (height) of the waves generated when the Brain moved his or her shoulder. 2. How close together were the crests (tops) of the waves generated when the Brain moved his or her shoulder? 3. Generally, how would you describe the frequency of the waves created when the Brain moved his or her shoulder? Check What You Know 1. Which wave; 1, 2 or 3, was the tallest? 2. Which wave; 1, 2 or 3, was the shortest? 3. Of the three waves your group created, which moved the fastest? 4. Of the three waves your group created, which moved the s l o w e s t? 5. How did Wave 1 compare to Wave 2? 13

6 6. How did Wave 1 compare to Wave 3? 7. What might have caused the differences between Wave 1 and Wave 3 observed by your group? 8. How did the movement of the Brain s hand, wrist and arm affect the frequency of each wave? 9. How did the movement of the Brain s hand, wrist and arm affect the amplitude of each wave? 10. Which wave represents higher energy, a wave with low amplitude and low frequency or a wave with high amplitude and high frequency? Why do you think this is true? Z Z Z ZZ 14