Light and Sound Waves Through Different Media

Light and Sound Waves Through Different Media

By Allison Childers

• 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

Multiple Choice

What is a wave?

• A disturbance that transfers matter

•  A disturbance that propagates energy through space or a medium

• A form of solid matter

• A stationary force

Multiple Choice

What type of wave is light?

• longitudinal

• transverse

• mechanical

• sound

Multiple Choice

What happens to the speed of light when it moves from air to water?

• it speeds up

• it slows down

• it remains the same

• it stops

Multiple Choice

Which of the following has the shortest wavelength on the EM spectrum?

• radio waves

• microwaves

• gamma rays

• infrared rays

• 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

Multiple Choice

Which of the following is a characteristic of mechanical waves?

• They can travel through the vacuum of space

• They require a medium to transfer energy

• they move slower in denser materials

• they are always longitudinal

Multiple Choice

Why can't mechanical waves travels though outer space?

• they require gravity to function

• space absorbs all wave energy

• they travel too fast to be detected

• there is no medium in space

Multiple Choice

What happens to mechanical waves when they travel from water to air?

• their speed remains the same

• they disappear

• they slow down

• they speed up

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

Conclusion

Multiple Choice

Which of the following is NOT an example of mechanical waves?

• sound waves

• ocean waves

• light waves

• water waves

Multiple Choice

What is the main difference between mechanical and electromagnetic waves?

• Mechanical waves transfer energy faster

• Electromagnetic waves require a medium

• Mechanical waves require a medium, but electromagnetic waves do not

• Electromagnetic waves cannot travel through solids