March 16 2015 Answer Brain Pop Quiz questions

March 16, 2015 • Answer Brain Pop Quiz questions as an anticipation guide (correct while viewing) • On the back, make a double bubble map comparing and contrasting transverse and longitudinal waves • Homework: Read and take notes on chapter 20, section 3. Skills tutor due Friday.

March 17, 2015 • • • Complete Parts of a Wave WS front & back Take out Anatomy of a Wave WS Take out 20. 3 notes Number a piece of paper 1 – 8 (skip spaces) Homework: Read and take notes on chapter 21, sections 1 & 2.

Investigations • • Rotate among the 8 activities Read the directions and complete the activity Record your observations Answer questions in italics

March 18, 2015 • Write a scientific argument based on yesterday’s activities • Take out your notes • Homework: Read and take notes: chapter 21, section 3 & 4. Skills. Tutor due Friday

March 20, 2015 • Read “Glassical Music” on page 6 of Current Science – pay attention to the vocabulary • Take out notes on chapter 21, sections 3 & 4 • No homework!

Glassical Music Answers • • • 1. friction 2. brain 3. high 4. distilled 5. wavelength • • • 6. compression 7. brain 8. vibrate 9. rarefaction 10. pitch

Waves, Sounds, and Light

Standards • SPS 9. Students will investigate the properties of waves. • a. Recognize that all waves transfer energy. • b. Relate frequency and wavelength to the energy of different types of electromagnetic waves and mechanical waves. • c. Compare and contrast the characteristics of electromagnetic and mechanical (sound) waves. • d. Investigate the phenomena of reflection, refraction, interference, and diffraction. • e. Relate the speed of sound to different mediums. • f. Explain the Doppler Effect in terms of everyday interactions.

A wave is a disturbance that transmits energy. The particles of a medium do not travel with the wave.

Mechanical waves require a medium, but electromagnetic waves do not

Particles in a longitudinal wave vibrate parallel to the direction that the wave travels. Particles in a transverse wave vibrate perpendicularly to the direction the wave travels. Link

Wave Properties • Amplitude is the maximum distance the particles of a medium vibrate from their rest position. • Wavelength is the distance between two adjacent corresponding parts of a wave. • Frequency is the number of waves that pass a given point in a given amount of time. • Wave speed can be calculated by multiplying the wave’s wavelength by the frequency.

Wavelength The shorter the wave, the higher the energy!

Frequency The higher the frequency, the higher the energy!

Wave Modeling Spring • How do transverse & compression waves compare? • How do they contrast? • What effect does increasing the energy into the wave have? • What relationship do you see between wave frequency and wavelength? • Waves on a String Ph. ET

Anatomy of a Wave • Part 1 – Label the wave according to directions • Part 2 – create waves on the back as follows:

Wave Interactions • Waves reflect after hitting a barrier. • Refraction is the bending of a wave when it passes through different media. • Waves bend around barriers or through openings during diffraction. • The result of two or more waves overlapping is called interference. • Amplitude increases during constructive interference and decreases during destructive interference. • Resonance occurs when a vibrating object causes another object to vibrate at one of its resonant frequencies.

Reflection: Waves reflect after hitting a barrier.

Refraction: The bending of a wave when it passes through different media.

Diffraction: Waves bend around barriers or through openings

The result of two or more waves overlapping is called interference. Amplitude increases during constructive interference and decreases during destructive interference.

Constructive & Destructive Interference • Ph. ET simulation • Demonstration

Resonance • Resonance occurs when a vibrating object causes another object to vibrate at one of its resonant frequencies. • Tacoma Narrows Bridge • Wine Glass

Practice • Which of the following results in more energy in a wave? • A. a smaller wavelength • B. a lower frequency • C. a shallower amplitude • D. a lower speed

Answer • Which of the following results in more energy in a wave? • A. a smaller wavelength • B. a lower frequency • C. a shallower amplitude • D. a lower speed

Practice • Refraction occurs when a wave enters a new medium at an angle because • A. the frequency changes. • B. the amplitude changes. • C. the wave speed changes. • D. the new medium changes.

Answer • Refraction occurs when a wave enters a new medium at an angle because • A. the frequency changes. • B. the amplitude changes. • C. the wave speed changes. • D. the new medium changes.

Practice • The bending of a wave as it passes at an angle from one medium to another is called • A. reflection. • B. refraction. • C. diffraction. • D. interference.

Answer • The bending of a wave as it passes at an angle from one medium to another is called • A. reflection. • B. refraction. • C. diffraction. • D. interference.

Sound • All sounds are generated by vibrations. • Sounds travel as longitudinal waves consisting of compressions and rarefactions. • Sound waves travel in all directions away from their source. • Sound waves require a medium through which to travel. Sound cannot travel in a vacuum. • Your ears convert sound into electrical impulses that are sent to your brain. • Exposure to loud sounds can cause hearing damage. • Using earplugs and lowering the volume of sounds can prevent hearing damage.

Properties of Sound • The speed of sound depends on the medium and the temperature. • The pitch of a sound becomes higher as the frequency of the sound wave becomes higher. Frequency is expressed in units of Hertz (Hz), which is equivalent to waves per second. • The Doppler effect is the apparent change in frequency of a sound caused by the motion of either the listener or the source of the sound. • Loudness increases with the amplitude of the sound. Loudness is expressed in decibels. • The amplitude and frequency of a sound can be measured electronically by an oscilloscope.

Sound requires a medium • Alarm clock in a bell jar demo

How We Hear: We lose the ability to hear higher pitches as we age. Damage to any part of the ear can cause deafness.

The speed of sound depends on the medium and the temperature.

The pitch of a sound becomes higher as the frequency of the sound wave becomes higher.

The Doppler effect is the apparent change in frequency of a sound caused by the motion of either the listener or the source of the sound.

Loudness increases with the amplitude of the sound. Loudness is expressed in decibels.