Light and Sound Waves Through Different Media

• Waves are disturbances that propagate energy through space or a medium.

• Waves transfer energy but not matter.

• Example: Ocean waves, sound waves.

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What are Waves?

• Mechanical Waves: Require a medium (e.g., sound, water).

• Electromagnetic Waves: Do not require a medium and can travel through a vacuum (e.g., light, radio waves).

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​Types of Waves

• Light is a transverse wave with both an electric field and a magnetic field.

• The two fields vibrate perpendicular (90 deg) to each other.

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Electromagnetic Waves (Light)

• EM waves occur in a variety of wavelengths called a spectrum.

• The longest wavelengths of radio waves which can be larger than the diameter of our planet.

• The smallest wavelengths of gamma rays and are significantly smaller than an atom.
  
  
  

​Types of EM Waves

• As light travels through more dense matter, it slows down. ex. air to water.

• Light waves travel slowest through solids.

• As light travels through less dense matter, it speeds up. ex. water to air.

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​Speed of Light Waves

• Require a medium (matter) to transfer energy.

• Transverse Waves: Vibrate perpendicular to wave direction (e.g., water waves).

• Longitudinal Waves: Vibrate parallel to the wave direction (e.g., sound waves).

Types of Mechanical Waves

• As a mechanical wave travels through more dense matter, it speeds up. ex. air to water.

• Mechanical waves travel slowest through gases.

• As a mechanical travels through less dense matter, it slows down. ex. water to air.

• Mechanical waves will not transfer energy in outer space. Space is very quiet.

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Speed of Mechanical Waves

Do not require a medium

examples: Visible light, x-rays

moves faster through air and slower through solids

​Electromagnetic Waves

Require a medium.

examples: sound, ocean waves

moves faster through solids and slower through air

Mechanical Waves