1. Longitudinal Waves
(longitudinal wave
(longitudinal vs. transverse)

2. It creates a longitudinal wave.
Essential Question (pg. 81): What happens if the medium vibrates the same way as the wave motion?
It creates a longitudinal wave.

3. Which direction does the medium vibrate in relation to the wave motion for a longitudinal wave?
It vibrates parallel to the wave motion.

4. Can a longitudinal wave travel in outer space?
No, longitudinal wave is a mechanical wave, meaning that it must travel through a medium and since there are no air particles in space, therefore, longitudinal waves cannot exist.
(stop at 3:25)

5. Your Question: What are compressions?
Places where particles of a medium crowd closer together.

6. Essential Question (pg. 85): How are sounds made? They are vibrations
in the form of
wave energy.

7. What must happen for us to hear a sound?
When an object vibrates it compresses surrounding air molecules and makes them vibrate. (each molecule makes the one next to it vibrate)

8. Can sound exist in space?
No, Because there are no particles in in space to vibrate. Therefore, There is no medium in space.

9. What is the difference between the pitch and the loudness of sound?
Pitch: depends on frequency,
meaning how many waves
are created in a given
amount of time.
Loudness: depends on
amplitude, which is the
intensity of the energy transferred.

10. What is the SI unit for:
Pitch: Hertz (Hz)
Volume: Decibels (dB)

11. Why does sound travel faster in solids than liquids:
Sound travels faster in solids than liquids, because in solids the particles are closer to each other, therefore, they can easily pass the energy of vibration to nearby particles.

12. Essential Question (pg
Essential Question (pg. 91): Why do cars sound different when they drive past me?
The perceived change in pitch and volume of a moving car passing a stationary person is due the Doppler Effect.

13. How will the sound of a train whistle change if the train is moving away from me?
The sound of the train will be
heard as a lower pitch and
volume, because as the
train moves away from a
stationary person, the
waves spread out behind
the train.

14. What causes the Doppler Effect?
Doppler effect happens when:
The source of sound is moving relative to the stationary listeners.
The source of sound is
stationary relative to the
moving listeners.

15. Do the Frequency and the amplitude of the sound source actually change?
No, they seem to be changing because the sound source is moving relative to the listeners.

16. Essential Question (pg
Essential Question (pg. 93): How does science help us understand how instruments work?
It helps us understand how “sound” is created as a result of vibrating of objects.

17. What do all musical instruments have in common?
They all create sound by causing matter to vibrate.
Most instruments use resonance to amplify sound.
Most instruments have a way of changing frequency of the sound.

18. What is resonance?
Resonance occurs when external vibrations match an object’s natural vibration or when vibration of one object causes another object to vibrate at the same frequency.
(tacoma bridge collapse)

19. Your Question: which part of the wave does resonance increase?
Resonance increases
amplitude of vibration.

20. Essential Question (pg. 97): How do scientists and engineers use sound?
They use sound in different technologies such as:
sonar to locate objects
like submarines underwater.
Ultrasonography to see
inside the human body.

21. How does a bat find its food at night?
Echolocation: It sends
out ultrasound waves
and use their echo/reflection
in order to locate objects
they cannot see.

22. How are sound waves used?
Echolocation: Animals such as bats and dolphins send out ultrasound waves and use their echoes (the reflected waves) to identify the location of objects they cannot see.
Sonar: Device that sends and receives ultrasound waves and uses the speed formula to find distance. (Distance = Speed x Time)
Ultrasonography: Used to see inside human body by sending harmless ultrasound waves.

23. Explain how a fisherman's’ fish finder works?
Uses a sonar system, which sends and receives ultrasounds to locate the fish.
(stop at minute 1:29)

24. What is the formula used to calculate distance?
Distance = Speed x Time

25. Law of Reflection
Bill nye:
Longitudinal vs. Transverse:
Frequency vs. volume
Breaking wine glass using resonance:
Washing machine breaking due to resonance: (start from 15 seconds)
How sonar works
Dolphins and bats
The Doppler Effect:
Resonance causing destruction (Tacoma bridge destruction, 1940)

26. Wave Medium Frequency
Mechanical waves Decibels Pitch
Transverse waves Electromagnetic waves
Longitudinal waves (compression waves)
Compression rarefaction amplitude
Wavelength Volume Hertz
Sound