Waves

Class Starter- Waves1) What are some examples of waves in nature?– ripples in a pond, a guitar string, an earthquake

2) How can we measure a wave?– Wavelength (LENGTH), – Frequency (SPEED), – Amplitude (HEIGHT)

3) What is the difference between a light wave and a sound wave?– Sound is a mechanical wave (more to come)– Light is an electromagnetic waves

4) What is the difference between a mechanical wave (SOUND) and an electromagnetic wave (LIGHT or RADIO)? Give an example of each:

A mechanical wave is a wave that requires a medium (solid, liquid, gas) in order to propagate (travel)

Ex: sound waves, water waves, seismic waves

An electromagnetic wave is a wave that can travel in both a vacuum and medium

Ex: radio waves, light waves, UV waves, X-waves, infrared waves, gamma waves

Mechanical Waves are…

• A mechanical wave, also called a material wave. It is a wave that needs a medium to travel.

• What is a medium? - generally it is classified as matter; it passes on

the energy from one molecule to the next, propagating the energy through space.

Transverse Wave Oscillation.

Longitudinal Wave Oscillation

Transverse Waves

Wavelength

Characteristics of Transverse Waves

Characteristics of Longitudinal Waves

Review Questions1) What kind of waves are sound waves?2) Does the speed at which sound travels change? Explain.3) What unit of measurement do we use to measure

sound intensity?4) What unit of measurement do we use to measure

sound frequency?5) What wave characteristic changes with different sound

intensity?6) What wave characteristic changes with different

tones/pitch?7) Do all living things perceive the same range of sound

wave frequencies?

8) What is the medium for:a. Water wavesb. Sound wavesc. Seismic waves

Answers1) What kind of waves are sound waves?

Sound waves are longitudinal, mechanical waves2) Does the speed at which sound travels change? Explain.

The speed of sound changes depending on the medium. For example, in air, sound travels at 340 m/s whereas in water, sound travels much faster, at at 1490m/s 3) What unit of measurement do we use to measure

sound intensity?Decibels (dB)

4) What unit of measurement do we use to measure sound frequency?

Hertz (Hz)

5) What wave characteristic changes with different sound intensity?

Amplitude changes with sound intensity. The louder the sound, the greater the amplitude of the wave.6) What wave characteristic changes with different

tones/pitch?The frequency of a wave determines its pitch.

Higher pitched tones have higher frequencies (and shorter wavelength) and lower pitched tones are lower frequencies (longer wavelength).7) Do all living things perceive the same range of sound

wave frequencies?No, different species have the ability to perceive a different range of sound frequencies.

9. What is the medium for:a. water waves? waterb. Sound waves? airc. Seismic waves? ground