1. SOUND
Science

2. What Makes Sound? vibration – a back and forth movement
energy transfer

3. How Does Sound Travel?
Sound is a vibration that travels through matter.
As vibration occurs, molecules in the air squeeze together and then spread apart.
compression – the part of sound wave where molecules are crowded together
rarefaction – the part of the sound wave where molecules are spread apart

4. Sound waves travel as compressional waves.

5. Sound waves can only travel through matter.
Sound waves need PARTICLES to travel.
Sound waves can only travel through matter.
Gases, liquids or solids

6. How Can You Change a Sound?
pitch – how high or low a sound is
Higher pitched sounds will have a greater frequency of sound waves.
frequency – the number of times an object vibrates per second
hertz – a unit for measuring frequency

7. Looking at amplitude
Amplitude measures how much energy is in the wave. Big amplitude = BIG SOUND

8. The pitch depends on how many vibrations there are.
The more frequent the vibrations the higher the note.
The fewer the vibrations the lower the note

9. What Makes Sound Loud? Energy of Sound Waves
Decibels – a unit for measuring loudness

10. Loudness Amplitude determines loudness.
An amplifier increases the amplitude of sounds.

11. Do Sounds Bounce?
reflection – the bouncing of a sound wave off a surface
Example – the crack of the baseball bat
absorption – the disappearance of a sound wave into a surface
Example – the sound of a baseball hitting the glove

12. What Is An Echo?
echo – a reflected sound wave

13. Ultrasound and Sonar
Sonar is a system that uses reflected sound waves for measurement and can measure large distances.