1. Complete Warm-Up for April 9th. Work with your shoulder partner first. Then swap and compare answers with the rest of your team. 4/9/122. The team with the most correct answers are “King/Queen for the day” and the D. Goldsberry rolling chairs.3. Get your journal ready. Add one page of guided notes to the next available page.4. Time Limit: 8 minutes
S8P5:Students will explore the 4/9/12wave nature of sound and D. Goldsberryelectromagnetic radiation.
a. Identify the characteristics of electromagnetic and mechanical waves.b. Describe how the behavior of light waves is manipulated causing reflection, refraction diffraction, and absorption). 4/9/12c. Explain how the human eye sees objects and colors in terms of wavelengths. D. Goldsberryd. Describe how the behavior of waves is affected by medium (such as air, water, solids).e. Relate the properties of sound to everyday experiences.f. Diagram the parts of the wave and explain how the parts are affected by changes in amplitude and pitch.
How can light and 4/9/12sound be used as D. Goldsberrytools?
What happens when a wavesencounters a boundary (a newmedium)? 1. Absorption 2. Reflection 4/9/12 3. Transmission – to pass through D. Goldsberry
1.Reflection2.Refraction 4/9/123.Diffraction D. Goldsberry4.Interference5.Polarization
occurs when a wave strikes an object and bounces off occurs with all types of waves 4/9/12 obeys the Law of Reflection – the D. Goldsberry angle of incidence is equal to the angle of reflection
When a wave enters a new medium at an angle, one side of the wave changes speed before the other side, causing the wave to 4/9/12 bend.• amount of bending depends on the speed of D. Goldsberry light in both materials• the greater the difference between the speeds of light in the two media, the more the light is bent
DIFFRACTION when a wave bends around an edge or spreads through an opening• familiar examples: sound waves (speakers in a room) and water waves (breaker opening in harbors)• the amount of diffraction increases with increasing λ D. Goldsberry 4/9/12
White light can be separated into the visible spectrum colors by bending 4/9/12 the light with refraction or diffraction D. Goldsberry red light is bent the least violet light is bent the most
• caused when light waves overlapeach othera) constructive – interact to build 4/9/12 up wave D. Goldsberryb) destructive – interact to reduce wave
INTERFERENCE when 2 or more waves meet while traveling in the same medium (overlapping waves) the NET displacement (amplitude) is the sum of the amplitude of the waves Constructive or destructive interference Creates standing waves & beats D. Goldsberry 4/9/12
Interference• the result of two or more sound• waves overlapping 4/9/12 D. Goldsberry
Interference• Waves combining• Constructive interference • Waves add together to make a larger amplitude 4/9/12 D. Goldsberry + + = =
CONSTRUCTIVE INTERFERENCE larger displacement (larger amplitude)crest overlaps crest or tough overlaps trough D. Goldsberry 4/9/12
CONSTRUCTIVE INTERFERENCE Resonance When an object vibration at a particular frequency Seen in musical instruments, especially strings Sympathetic resonance When one vibrating object induces a vibration in another object Soldiers do not walk in formation across bridges Tacoma Narrows Bridge D. Goldsberry 4/9/12
Interference (cont.)• Destructive interference • Waves add together to make a smaller amplitude 4/9/12 D. Goldsberry + + = =
DESTRUCTIVE INTERFERENCE smaller displacement (smaller amplitude)crest overlaps trough displacement/ amplitude is reducedcrest cancels trough D. Goldsberry 4/9/12
4/9/12 D. GoldsberryDifferent sounds that you hear include(A) noise, (B) pure tones, and (C) musicalnotes.
BEATS: INTERFERENCE Overlapping waves of different f (frequencies) In music interference creates “beats” (changes in loudness & softness) Wave 1 (red) and Wave 2 (blue) combine to form beat pattern (in green) High amplitude = LOUD Low amplitude = soft D. Goldsberry 4/9/12
A polarizing filter acts as thoughit has tiny slits in one direction. 4/9/12Only some of the light (vibrating inthe same way as the slit) can pass D. Goldsberrythrough a polarized filter