Parts of a Wave…Crests= top of the wave

Troughs= bottom of the wave

Wavelength

Let’s Learn Wave Vocabulary…

Cycle

= How many waves are made per second, or as cycles per second. The greater the frequency, the more waves you have.

Frequency

Frequency of WavesIf ten waves are made per second, then the

frequency is said to be ten cycles per second, written as 10 cps.

Usually, we use the unit Hertz to state frequency.

Anyone ever heard of Hertz before?The unit Hertz is abbreviated this way:1 Hertz = 1 Hz1 cps = 1 Hertz

What are Electromagnetic Waves?Electricity can be static, like what holds a

balloon to the wall or makes your hair stand on end.

Magnetism can also be static like a refrigerator magnet. But when they change or move together, they make waves - electromagnetic waves.

Electromagnetic waves are formed when an electric field combines with a magnetic field. These different waves make up the Electromagnetic Spectrum!

Electromagnetic WavesEM Waves all carry a single form of energy

called electromagnetic (radiant) energy which originates from the sun.

The electromagnetic spectrum includes, from longest wavelength to shortest: radio waves, microwaves, infrared, visible, ultraviolet, X-rays, and gamma-rays.

Electromagnetic Spectrum Weakest

Strongest Waves Waves

As the wavelengths of light decrease, they increase in energy. Low frequency high frequency

Radio WavesRadio waves are found at

the longest wavelengths, on the electromagnetic spectrum.

These are the light waves that are used to send signals to radios and televisions (non-cable).

Longest wave lengthLow frequencylowest energy

Microwaves Microwaves are used in radar

because they can penetrate haze, light rain and snow, clouds, and smoke.

Used to study the universe and communicate with satellites that orbit earth.

Microwaves are also used to heat your food! Microwaves are used in radar because they can penetrate haze, light rain and snow, clouds, and smoke.

Used to study the universe and communicate with satellites that orbit earth.

Microwaves are also used to heat your food!

Infrared WavesInfrared radiation is what

we like to describe as heat. We can't see infrared waves, but we can feel them. Your body gives off heat, so it is an emitter of infrared radiation.

Infrared waves are often used in fast food restaurants to heat food!

They are also used in satellite pictures to detect invisible infrared waves.

Visible Light WavesVisible light is the light

that we can see and thus is the only light detectable by the human eye.

White light is visible light, and it contains all the colors of the rainbow, from red to violet.

Visible Light WavesAfter observing the visible

light chart to the right, explain why we use “red light waves” for lasers pointers” instead of purple light waves?

Answer: We use “Red” light waves for laser pointers because they have longer wave lengths which equals weaker frequencies. Purple wave lengths have stronger wave lengths= stronger frequencies.

Ultraviolet WavesUltraviolet light is the

radiation from the sun that causes a sunburn when you have been outside too long on a sunny day.

You can't see ultra-violet light, so you can still get sunburned on a cloudy day!

Though these waves are invisible to the human eye, some insects, like bumblebees, can see them!

How bees use Ultraviolet WavesWe see the flower in visible light!

Bees however see the flower in Ultraviolet light that we can’t see!

X-Ray WavesX-rays are very energetic

and are used in X-ray machines to take pictures of your bones or teeth.

The Sun also emits X-rays - here is what the Sun looked like in X-rays on April 27th, 2000.

Gamma WavesGamma rays are the most

energetic light waves found on the electromagnetic spectrum. Gamma rays are released in nuclear reactions and particle collisions.

Gamma-rays can kill living cells so they can be used in medicine to kill cancerous cells.

Shortest wave lengthHigh frequencyHighest energy

Gamma-ray bursts can release more energy in 10 seconds than the Sun will emit in its entire 10 billion-year lifetime!

Reflection of WavesWhen we wear sun

block at the beach it helps to reflect the sun’s harmful rays.

SPF (sun protection factor)

Absorption of EM WavesAbsorbing too much of

the sun’s radiant waves. = sunburn!

Greenhouse Warming/ Greenhouse Effect= The Earth absorbing heat from the sun’s radiant energy.

Microwave cooking- When our food absorbs microwaves and is heated up.

Absorption of Electromagnetic Waves can also be used for… X-rays can be used to detect broken

bones beneath the skin.

Coating on eyeglasses and sunglasses protect the eyes by permitting visible waves to pass but absorb UV waves.

RefractionThe wave can pass through and into a material

Diffraction

The wave can bend around or through holes in an obstacle.

Types of Earthquake Waves

aka: Seismic Waves

Measuring Earthquake Magnitude- A measure of the amount of energy released by an earthquake, as indicated on the

Richter Scale. Se

ism

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Earthquake data: Seismogram

Tsunami wavesA tsunami is not a single wave but a series of

waves, also known as a wave train. The first wave in a tsunami is not necessarily the most destructive. Tsunamis are not tidal waves.

Tsunami waves can be very long (as much as 60 miles) and be as far as one hour apart. They are able to cross entire oceans without great loss of energy. The Indian Ocean tsunami traveled as much as 3,000 miles (nearly 5,000 kilometers) to Africa, arriving with sufficient force to kill people and destroy property.

Tsunami wavesWhere the ocean is deep, tsunamis can travel

unnoticed on the surface at speeds up to 500 miles an hour (800 kilometers an hour), crossing an ocean in a day or less. Scientists are able to calculate arrival times of tsunamis in different parts of the world based on their knowledge of water depths, distances, and when the event that generated them occurred.