SCIENCE: Waves

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Waves

Disturbances that propagate through space and carry energy without the medium moving with the wave

Wave Pulse

A single disturbance that propagates through space

Medium

A substance that waves travel through and need to move through

Mechanical Waves

Waves that need a medium to move

Seismic Waves

Mechanical waves that move through the ground

Sound Waves

Mechanical waves that move through solids liquids and gases

Surface Waves

Mechanical waves that move through water

Electromagnetic Waves

Waves that can travel through empty space without a medium

Transverse Waves

Waves in which the medium moves up and down perpendicular to the direction of wave propagation

Longitudinal Waves

Waves in which particles move left to right and right to left parallel to the direction of wave propagation

Compression

A region in a longitudinal wave where particles are packed together

Rarefaction

A region in a longitudinal wave where particles are far away from each other

Crest

The highest point of a wave

Trough

The lowest point of a wave

Amplitude

The distance between the crest or trough and the equilibrium position

Wavelength

The length of one complete wave cycle measured from crest to crest or trough to trough

Wavelength Unit

Wavelength is commonly measured in meters or angstroms

Angstrom

A unit of wavelength equal to 10⁻¹⁰ meters

Nanometer

A unit of length where one meter equals 1

Wave Speed

How fast a wave travels from one point to another

Wave speed is calculated using v = d/t

TRUE

Frequency

The number of waves that pass a fixed point per second

Hz or Hertz

It is the unit of measurement for frequency

Frequency is calculated using f = 1/T

TRUE

Period

The time it takes a wave to travel a distance equal to one wavelength

Period Equation

T = 1/f

Wave Velocity

The distance traveled by a wave crest over a given period

Wave Velocity Equation

v = λ/T

Reflection

The bouncing off of waves when they hit a surface they cannot pass through

Effect of Reflection on Wave Speed

Reflection does not change the wave speed

Effect of Reflection on Frequency

Reflection does not change the wave frequency

Flipped Wave

A reflected wave can be flipped upside down

Refraction

The change in wave speed and direction when a wave encounters a change in medium

Refraction and Bending

A greater change in wave speed causes more bending

Electromagnetic Radiation

Energy that has properties of waves and can also be thought of as a stream of particles

Electric Charge

A charged particle that can oscillate and produce electromagnetic waves

Oscillating

Changing or moving back and forth repeatedly

Oscillating Charge

An electric charge that moves back and forth in a repetitive periodic pattern

Oscillating Electric Field

An electric field whose strength and direction change back and forth in a periodic wave-like pattern over time

Oscillating Magnetic Field

A magnetic field whose strength and direction change back and forth periodically over time usually driven by alternating current

Electromagnetic Wave Production

Electromagnetic waves are produced by oscillating electric charges

Electric Field

A field produced by electric charges that changes and produces a changing magnetic field when the charge oscillates

Magnetic Field

A field that changes in response to a changing electric field and vibrates together with it

Perpendicular

Positioned at a right angle to another direction or object

Electromagnetic Wave Fields

The electric and magnetic fields of an electromagnetic wave vibrate perpendicular to each other and to the direction of propagation

Electromagnetic waves are transverse waves because their vibrations are ? to their direction of propagation

perpendicular

Electromagnetic Waves and Medium

Electromagnetic waves do not require a medium and can travel through empty space

Electromagnetic waves carry no electric charge

TRUE

Energy Transfer by EM Waves

Electromagnetic waves move energy from one place to another

Electromagnetic waves follow the laws of reflection

TRUE

Electromagnetic waves follow the laws of refraction

TRUE

The equation v = fλ is appropriate for all ? waves

Electromagnetic

Speed of Light

The speed at which electromagnetic waves travel in empty space approximately 3.0 × 10⁸ meters per second

Electromagnetic waves travel around ?

300,000 km

Because electromagnetic waves travel at a constant speed, their wavelength is ? proportional to their frequency

inversely

When the frequency of an electromagnetic wave increases, its wavelength becomes ?

shorter

Speed of Light Equation

The relationship between speed of light frequency and wavelength is c = fλ

c

The symbol representing the speed of light

f

The symbol representing frequency or the number of waves per second

λ

The symbol representing wavelength or the distance between waves

Light as a Wave

Light behaves as a transverse wave and can be filtered using polarized lenses

Light

it can be thought of as a stream of particles called photons

Photon

A particle of electromagnetic radiation that can interact with matter

Photoelectric Effect

The effect in which directed light can knock electrons off a substance

The frequency of electromagnetic waves does not change when they travel through different media

TRUE

Electromagnetic Spectrum

The continuous range of frequencies containing electromagnetic waves arranged in order of increasing frequency

Radio Waves

Electromagnetic waves with the longest wavelengths and lowest frequencies

Modulation

Variation in either the frequency or amplitude of a wave

Infrared Rays

Electromagnetic waves with shorter wavelengths and higher frequencies than microwaves

Visible Light

Electromagnetic waves that humans can see

Visible light has ? wavelengths and ? frequencies than infrared rays

shorter, higher

Red Light

Visible light with the longest wavelength

Violet Light

Visible light with the shortest wavelength

Ultraviolet Rays

Electromagnetic waves with shorter wavelengths and higher frequencies than visible light

Ultraviolet Energy

rays that carry more energy than visible light