WAVES-Sound & Light

Waves and Their Applications in Technologies for Information Transfer

Can you think of a time you've ever seen sound? Usually, people think of hearing sound, not seeing it.

How can you see sound?

Frequency

Frequency is a measure of how many waves pass a point in a certain amount of time.
The higher the frequency, the closer the waves are together and the greater the energy carried by the waves will be

Speed

Speed is a measure of the distance a wave travels in an amount of time.
The speed of a wave is determined by the type of wave and the nature of the medium.
As a wave enters a different medium, the wave’s speed changes. Waves travel at different speeds in different media.
All frequencies of electromagnetic waves travel at the same speed in empty space.

Wavelength

Wavelength is a measure of the distance from the crest on one wave to the crest on the very next wave.
Shorter wavelengths are influenced by the frequency.
A higher frequency causes a shorter wavelength and greater energy.

Amplitude

Amplitude is a measure of the distance between a line through the middle of a wave and a crest or trough.
The greater the force that produces a wave, the greater the amplitude of the wave and the greater the energy carried by the wave.
The highest point of a transverse wave is the crest and the lowest point is called a trough.
In a transverse wave the higher the wave, the higher the amplitude.
Sounds with greater amplitude will be louder; light with greater amplitude will be brighter.

Transmission

Transmission of waves occurs when waves pass through a given point or medium.
Sound waves are transmitted through solids, liquids, and gases.
Light waves are transmitted through transparent materials (may be clear or colored material such as filters) that allow most of the light that strikes them to pass through them.
Only a small amount of light is reflected or absorbed.
Opaque materials allow no light waves to be transmitted through them.
Translucent materials transmit some light, but cause it to be scattered so no clear image is seen.

Absorption

Absorption of certain frequencies of light occurs when the energy is not transferred through, or reflected by, the given medium.
Objects or substances that absorb any wavelength of electromagnetic radiation become warmer and convert the absorbed energy to infrared radiation.

Reflection

Reflection is the bouncing back of a wave when it meets a surface or boundary that does not absorb the entire wave’s energy.
All types of waves can be reflected.
Reflections of sound waves, for example, are called echoes and help bats and dolphins learn about their environments.
Plane mirrors and other smooth surfaces reflect light to form clear images.

Refraction

Refraction is the bending of waves caused by a change in their speed as they pass from one medium to another.
As waves pass at an angle from one medium to another, they may speed up or slow down.
The greater the change in speed of the waves, the more the waves will bend.
Refraction of light going from air through a convex lens, for example, can make images appear larger as the light waves bend.
Prisms or diffraction gratings separate white light into its different components or colors by bending the light at different angles depending on the frequencies of the light passing through the prism or diffraction grating. Different colors of light have different frequencies.