Wave Interactions Teaching Slides PDF

Turn and talk: Notice and Wonder Instructions: Look at the image and write down 2-3 things you notice (key details, main ideas, themes) and then write down 2-3 things you wonder (questions you have because of the image, things you are curious about when you look at the image.).Discuss your observati...

Turn and talk: Notice and Wonder Instructions: Look at the image and write down 2-3 things you notice (key details, main ideas, themes) and then write down 2-3 things you wonder (questions you have because of the image, things you are curious about when you look at the image.).Discuss your observations with your partner then share with the class. Notice What do you notice? Wonder What do you wonder? 1  TOPIC 8:Waves LESSON 2– Waves Interactions  Standard: PS-MS-PS4-2 Develop and use a model to describe that wavesare reflected, absorbed, or transmitted through various materials. LEARNING OBJECTIVES Day 1: Define wave interactions (reflection, refraction, absorption).  Identify examples of each type of wave interaction in real life. Vocabulary Reflection Refraction Absorption  Diffraction Interference Reflection When a wave strikes a medium it can not pass, the wave bounces off. Energy is not absorbed or converted to another form, but are reflected from an obstruction. Think about a time when you saw a wave or you bounced off something. What happened? How did it make you feel? Surfaces and how they affect reflection The Law of Reflection The angle of incidence equals the angle of reflection E.g. Mirrors and Echos  LEARNING OBJECTIVES Day 2: Explore the principles of reflection and refraction through hands-on activities. Analyze how these interactions affect wave behavior. Refraction When a wave enters a new medium (not perpendicular), it bends because the wave changes speed Note: the straw is not bent, the image just appears distorted due to refractionMedium #1 = Air Medium #2 = Water Think of when you ride a bike.What happens when you move from a smooth to rocky surface? The wave travels faster in air The wave slows down in water  Air into Glass Glass into Air  the light changes speed twice Diffraction Bending of a wave around a barrier or through an opening. Think about how you can hear someone around the corner? Waves do NOT always travel in straight lines  Absorption What do you think of when you hear the word absorption? Some waves can be absorbed by certain materials Energy of the wave is transferred to the material - think of waves when they reach the shore. Why does Black appear Black and White appear White? the black object appears reflect any light black because it absorbs the white object appears all light, and does not white because it reflects all light, and does not absorb any light Classify each of the following Reflection, refraction, diffraction or absorption? Wave Interference When they collide, they become bigger until they go in their original direction Constructive Interference occurs when 2 waves of similar size collide and combine to create a wave with larger amplitude - They “help” each other “wave addition” “amplitude addition” Destructive Interference  occurs when 2 waves combine to create a wave withsmaller amplitude. The crest of one overlaps the trough of another “wave subtraction” “amplitude subtraction”  Question Which one is constructive interference? A or B? AB  Standing Waves A wave that appears to stand in one place. Happens when two waves interfere with each other when they are in opposite directions. They are in the right frequency. Watch youtube video now. Standing Waves  Nodes and Antinodes Destructive interference between the waves causes points with zero amplitude - Nodes Always evenly spaced Halfway between the nodes, and at maximum amplitude - antinodes Standing Waves Frequency and wavelength of interfering waves determine number of nodes and antinodes. Question time! Q. How many nodes and antinodes are in each standing wave? Resonance Have you ever been on a swing? Resonance Ever heard of Tacoma bridge? Watch video https://www.youtube.com/watch?v=XggxeuFDa DU Resonance Most objects have a natural frequency or vibration. Standing waves can occur in an object when it vibrates at its natural frequency. Watch video: https://www.youtube.com/watch?v=ATRzwhk7 UvY Resonance Resonance is an increase in the amplitude of a vibration that occurs when external vibrations match an objects natural frequency. Question How is a wave created? 1. vibrations 2. compressions 3. frequencies 4. rarefactions Question Give me an example of a music instrument that uses standing waves and resonance