INTRODUCTION

Waves are everywhere!  Spiders detect prey by the vibrations of their webs, cars oscillate up and down when they hit a bump, buildings and bridges vibrate when heavy trucks pass or the wind is fierce. Electrical oscillations occur in radio and television sets. At the atomic level, atoms vibrate within a molecule, and the atoms of a solid vibrate about their relatively fixed positions.

Vibrations and wave motion are intimately related subjects. Waves whether ocean waves, waves on a string, earthquake waves, or sound waves in airhave as their source a vibration. In the case of sound, not only is the source a vibrating object, but so is the detectorthe eardrum or the membrane of a microphone. Indeed, the medium through which a wave travels itself vibrates (such as air for sound waves).

In this PhysicsQuest you will learn about  the nature and properties of waves. You will see how waves behave at boundaries and how standing waves are formed.

PhysicsQuest

WAVES

TASK

You will read each section and answer the questions given.

PROCESS AND RESOURCES

NATURE OF A WAVE

1. Define the following terms:

a) wave

b) equilibrium position

c) disturbance

d) pulse

e) medium.

2. What is meant when we say that a wave is an energy transport phenomenon.

WAVE CATEGORIES

Waves can be categorized in two ways:

I. on the basis of the direction of movement of the individual

particles of the medium relative to the direction which the waves

travel and

II. on the basis of the ability to transmit energy through a vacuum.

3. Name the three types of waves on category I.

   Give its characteristics and one example of each.

4. Name the two types of waves on category II.

   Give its characteristics and one example of each.

LONGITUDINAL WAVES AND GUITAR STRINGS

A guitar string vibrating by itself does not produce a very loud sound.

5. Explain how we can hear the sound from a guitar.

BEHAVIOR OF WAVES

As a wave travels through a medium, it will often reach the end of the medium and encounter an obstacle or perhaps another medium through which it could travel.

6. Explain what is meant by a boundary and boundary behavior.

Consider a pulse moving through a medium (a rope).

7. Compare the behavior of the wave when:

A. It is fixed at one end.

B. When it is free at one end.

Watch the animation:TRANSMISSION OF A PULSE

The animation shows the boundary behavior of a pulse that is moving along a less dense medium into a more dense medium.

8. Answer the following questions:

A. Compare the wave speed in both mediums.

B. Compare the wavelength in both mediums.

C. Compare the frequency in both mediums.

D. Compare the amplitude in both mediums.

E. Describe the reflected pulse in both mediums.

STANDING WAVES

A standing wave pattern is an interference phenomenon.

9. Describe the formation of a standing wave and define a node and an antinode.

HARMONICS

10. Define a harmonic:

Complete each question:

11. The frequency associated with each harmonic depends on: _____

12. The speed at which waves move through a medium depends on: _____

13. The wavelength of the harmonic depends on: _____

DOPPLER EFFECT

Briefly describe:

14. The Doppler Effect.

15. The formation of shock waves.

16.  A sonic boom.