1. Wave Motion Waves are caused by vibrations. Their displacement is symmetrical about a point.

2. Properties of Waves Waves are not matter. A wave is a disturbance that transfers energy. If you send a pulse through a rope, the rope moves back to rest after the wave has passed through. If this vibration occurs as a repeated pattern over regular time intervals, it is referred to as periodic motion.

3. Types of Waves Mechanical waves are waves that require a medium for travel. Electromagnetic waves do not require a medium. They travel at the speed of light.

4. Transverse Longitudinal

5. Transfer between Media The speed of a wave depends upon the medium through which it is travelling. Friction can decrease the amplitude of a wave and therefore takes away energy, but it will not change the speed of the wave. When a wave moves from one medium into another, the frequency of the wave remains the same but the speed changes. When a wave encounters a boundary between two media, some of the wave is transmitted through the boundary and some is reflected from the boundary. The amount of wave reflected depends on how different the two media are – the more different they are, the more of the wave that will be reflected.

6. When a pulse travels from a heavy medium (slower) to a lighter medium (faster), the reflected pulse is on the same side of the spring as the incident pulse. When an incident pulse in a light medium encounters a heavier medium, some of the wave is still transmitted into the heavier medium and this transmitted pulse is still on the same side of the medium as the incident pulse. The reflected pulse is always on the opposite side of the medium compared to the original incident pulse.

7. Superposition & Interference When waves collide they simply pass through one another unchanged. They behave as if there is no interaction. While the waves overlap, they temporarily interfere with each other. The displacement of the medium is the sum of the displacements of each component wave. This is called interference.

8. Constructive Interference

9. Destructive Interference

10. Resonance When energy is added to at the same frequency as its natural frequency, resonance will occur. The frequency (or frequencies) at which an object tends to vibrate when disturbed is known as the natural frequency of the object

11. Period & Frequency Period (T) is the time it takes to complete one cycle. Period = time for the cycles number of cycles What is the period of a raindrop if there are 10 rain drops in 7.5 seconds? T = 7.5s 10 cycles T = 0.75 s

12. Frequency (f) is the number of cycles in one second. f = number of cycles time for the cycles What is the frequency of a raindrop if there are 10 rain drops in 7.5 seconds? f = 10 cycles 7.5 seconds f = 1.3 Hz

13. A child swings back and forth on a swing 15 times in 30.0 s. Determine the frequency and period of the swing.

14. The ___?___ of a wave depends only on the medium in which it is travelling. a. Frequencyb. Period c. Speedd. Wavelength When a wave passes from one medium to another, the ___?___ must stay the same. a. Amplitudeb. Frequency c. Speedd. Wavelength

15. A wave in which the medium moves parallel to the medium is called a ___?___ wave. a. Electromagneticb. Longitudinal c. Mechanicald. Transverse The vertical distance from the top of a crest to the bottom of a trough is 34.0cm. The amplitude of this wave is a. 8.5 cmb. 17.0 cm c. 34.0 cmd. 68.0 cm

16. A pulse goes into a medium that is less dense. The reflected pulse is ___?___. a. Fasterb. Inverted c. Largerd. Upright Resonance occurs when one object causes a second object to vibrate. The second object must have the same natural ___?___. a. Amplitudeb. Frequency c. Speedd. Wavelength A wave has a period of 0.20 s. What is the frequency? a. 0.20 Hzb. 1.0 Hz c. 5.0 Hzd. 20. Hz