Sound Powerpoint presentation for grade 7..pptx

sound

1. SOUND Prepared by: Karen Mae Castro

2. Objectives: Describe the characteristics of sound using the properties of waves Demonstrate the changes in the pitch and loudness of sound Explain the production of sounds in the human voice box Discuss how pitch, loudness, and quality of sound vary from one sound to another Describe how organisms produce, transmit, and receive sounds of various frequencies Create harmonious music using recyclable materials

3. Table of Contents: M ediums of Sound transmission How we hear sounds L esson 1: Transmission of Sounds L esson 2: Pr operties of Sound Pitch Doppler Effect Echolocation Loudness Quality Les son 3: Musical Instruments Stringed Instruments Wind Instruments Percussion Instruments

4. What is Sound Wave? Vibrations are back and forth motions that create sound. Sound wave is produced when an object vibrates rapidly in a medium like air.

5. Compressions - The close together part of the wave Rarefactions – the spread-out parts of a wave

6. In which media does sound travel fastest? In Solid? In Liquid? Or In Gas?

7. Sounds travel faster in solids than in liquids and faster in liquid than in gases. Sound travels better through high-density materials. The closer the molecules are together, the faster they can collide and transfer energy.

8. H earing and the Human Ea r The Outer Ear it is a sound collector. It consists of the part that you can see and the ear canal. The visible part is shaped somewhat like a funnel. This shape helps the visible part to collect sound waves and direct them into the ear canal.

9. Sound waves that pass through the ear canal cause the ear drum to vibrate. These vibrations are transmitted to the three small bones, which amplify the vibrations. The Middle Ear - it is a sound amplifier. It consists of the ear drum and three tiny bones called hammer, the anvil, and the stirrup.

10. The Inner Ear it contains the Cochlea. The cochlea is filled with fluid and is lined with tiny hair-like cells. Vibrations of the stirrup bone are transmitted to the hair cells. The movement of the hair cells produce signals that travel to your brain, where they are interpreted as sound .

11. Properties of Sound

12. P roperties of Sound Pitch description of how high or low the sound seems to happen Frequency - number of sound waves that passes through a point in a certain amount of time, such as one second.

13. The greater the frequency, the higher the pitch. Hertz (Hz) is the unit to measure frequency and pitch.

14. K ind s of Sound Waves 1. AUDIBLE SOUND Human can hear (20 – 20 000 Hz) 2. ULTRASONIC WAVES Above 20 000 Hz Cannot be detected by human ear but some animals do. Dogs can detect as high as 50 000 Hz and bats can hear up to 100 000 Hz. Uses in Ultrasound

15. Loudness How loud or soft a sound is perceived to be. Determined mainly by the amplitude of the sound wave. Decibel (dB) is the unit used to measure sound intensity or loudness.

16. SONAR SONAR stands for Sound Navigation And Ranging. It uses ultrasonic waves to measure the distance, direction and speed of underwater objects.

17. ECHOLOCATION Similar to SONAR It is used by some animals like bats and dolphins. Bats and Dolphins use this echolocation to navigate, find food and avoid predators.

18. 3. INFRASOUND Sound below 20 Hz SOURCES OF INFRASOUND: Vibrating heavy machines Earthquakes Thunder Volcanoes It cannot be heard by human ear but can cause damage.

19. QUALITY / TIMBRE The difference among sounds of the same pitch and loudness. The quality of a sound depends on the waveform of the sound wave. TWO DIFFERENT WAVEFORMS Pure Tone – simplest waveform, it has a soft, pleasant tone quality and sinusoidal Complex Tone – nearly sinusoidal.

20. MUSIC VS NOISE MUSIC Created using specific frequencies and sound quality and by following a regular pattern. Pleasant to the ears. NOISE Has no definite pitch and pattern. Consider as unpleasant to the ears.

21. DOPPLER EFFECT A change in the frequency and pitch of sound due to either movement of the source or the listener. Example: Observe the siren of an ambulance car, the pitch is increases as the ambulance car approaches you. As it moves away, the siren’s pitch decreases.

22. A. REFRACTION OF SOUND Change in direction, as the wave moves away from one medium to another. It bends or refracts as they move through air.

23. B. REFLECTION OF SOUND Echo Reflected sound It is what you heard shortly after the original.

24. C. DIFFRACTION OF SOUND Sound waves bend or diffract around corners or barriers like doors and walls.

25. D. INTERFERENCE The result of two or more sound. Waves overlapping

26. 2 Types Constructive Interference The sound waves arrive at the same time and phase. Destructive Interference Waves arrive at interval and are out of phase.

27. RESONANCE The inducing of vibrations of a natural rate by vibrating source having the same frequency.

28. STRINGED INSTRUMENTS MUSICAL INSTRUMENTS Violins and guitars are some example of stringed instruments. They produces sounds when their strings vibrate by rubbing them with a bow, or by strumming or plucking them.

29. . . WIND INSTRUMENTS Brass instruments like trumpets and woodwind instruments like flutes. In Brass instruments, sounds are produced when a musician’s lips vibrate against the mouthpiece causing the air column to vibrate. Woodwind instrument contain a thin flexible strip of material called reed . It produces sounds when the reed vibrates causing the air column in the instrument to vibrate

30. PERCUSSION INSTRUMENTS It includes drums, cymbals and xylophone. These instruments vibrate when struck. You control the sound intensity by how hard you strike

31. THANK YOU! & GOD BLESS!!!