Today’s Agenda 12/7/15 Check out the Waning Crescent Moon (17% visible) Moonrise 3:05AM Moonset 2:15PM & the constellation Orion ! Homework No Homework Homework Revisit Exploring Space Introduction to the Electromagnetic Spectrum Revisit Exploring Space Introduction to the Electromagnetic Spectrum

The Electromagnetic Spectrum And “Wavestown”

Electromagnetic Waves Transverse waves without a medium! (They can travel through empty space)

The Electromagnetic Spectrum electromagnetic spectrum radiationThe electromagnetic spectrum is just a name that scientists give a bunch of types of radiation when they want to talk about them as a group.

Long Wavelength = Low Frequency Short Wavelength = High Frequency

Radio Waves RadioRadio: yes, this is the same kind of energy that radio stations emit into the air for your radio to capture and turn into your favorite George Strait, Rihanna, or Faith Hill tunes. But radio waves are also emitted by other things:... such as stars and gases in space. Car radios, cell phones, T-Vs, CB radios, and walkie talkies all use radio waves!

Microwaves MicrowavesMicrowaves: they will cook your popcorn in just a few minutes! o Besides microwave ovens and cell phones, other devices using the microwave range include: o GPS o WiFi o Cordless home phones o Police Traffic Radar o Military radars (e.g. ships, airplanes and satellites - these ones can put out A LOT of power, and great caution must be taken to keep people away from the antennas because they can and will cook you like a microwave oven if you get really close, like a few feet away.)

Infrared Waves Infrared (IR) 'heat',Infrared (IR): we often think of this as being the same thing as 'heat', because it makes our skin feel warm. Other ways we use infrared: cameras militaryfirefightingThere are cameras that can pick up infrared energy, many used in the military and in firefighting (helps locate people in smoke filled homes). ScopesScopes on weapons can use infrared (night vision). “heat lamps”We use “heat lamps” to warm our food (restaurants) and to keep our animals warm during cold nights. TelescopesTelescopes used to study the stars can pick up infrared energy.

Infrared The image below of the center region of our galaxy was taken by IRAS (in infrared). The hazy, horizontal S-shaped feature that crosses the image is faint heat emitted by dust in the plane of the Solar System.

Visible Spectrum Visible:Visible: yes, this is the part that our eyes see. Visible radiation is emitted by everything from fireflies to light bulbs to stars... also by fast-moving particles hitting other particles. How many objects can you think of that release light? I am sure there are hundreds!

Light Spectrum

Visible Light prismLight can be broken down into the colors of visible light with a prism.

Visible Light Spectrum

Rainbows

Ultraviolet Ultraviolet:Ultraviolet: we know that the Sun is a source of ultraviolet (or UV) radiation, because it is the UV rays that cause our skin to burn! Stars and other "hot" objects in space emit UV radiation. sunglassesPeople wear sunglasses to protect their eyes from the dangerous UV radiation. Tanning salonsTanning salons use this same energy in their tanning beds. ultraviolet lampsThere are ultraviolet lamps that are used to kill bacteria and sanitize areas. large telescopesWe also use large telescopes to study the release of UV radiation from objects in space.

Skin Damage from UV Radiation

Our Sun’s Harmful Ultraviolet Waves ultraviolet waves sunburnsOur Sun emits light at all the different wavelengths in electromagnetic spectrum, but it is ultraviolet waves that are responsible for causing our sunburns. Picture showing the UV waves coming from the sun.

Ultraviolet Ultraviolet (UV) light has shorter wavelengths than visible light. Though these waves are invisible to the human eye, some insects, like bumblebees, can see them!

X-Rays X-RaysX-Rays: your doctor uses them to look at your bones and your dentist to look at your teeth. Hot gases in the Universe also emit X-rays. X-raysWe use X-rays to: –look inside our bodies, –X-ray machines at airports to look inside luggage –X-ray detectors to find x-ray energy around our atmosphere in in space –X-ray telescopes to study the universe universe

How we use x-rays

Gamma-Rays Gamma-raysGamma-rays: radioactive materials can emit gamma- rays. “gamma ray burst”When massive stars supernovae, they release a tremendous amount of energy in a “gamma ray burst” How we use gamma radiation:How we use gamma radiation: cancer treatmentcancer treatment measure soil densitymeasure soil density at construction sites ensure the proper fill level for packages of food, drugs and other products. sterilize medical equipmentsterilize medical equipment in hospitals pasteurize certain foods and spicespasteurize certain foods and spices gauge the thickness of metal in steel mills.gauge the thickness of metal in steel mills. Click on the pic

Gamma-rays But the biggest gamma-ray generator of all is the Universe! It makes gamma radiation in all kinds of ways.

The Moon in Gamma-Rays The gamma-ray moon just looks like a round blob - lunar features are not visible. In high-energy gamma rays, the Moon is actually brighter than the quiet Sun. This image was taken by EGRET.

The Electromagnetic SpectrumRadio Microwave Infrared Ultraviolet X-ray Gamma Red Orange Yellow Green Blue Violet VisibleLight The electromagnetic spectrum is just a name that scientists give a bunch of types of radiation when they want to talk about them as a group.

“Wavestown” 1.Study the picture of the town. 2.Fill in the Electromagnetic spectrum below the picture with the different forms of radiation in the proper order. 3.Color in the light spectrum (ROYGBV). 4.Identify the forms of radiant energy in the picture by numbering each example. –On the following slide, the antennae on the Taxi is an example of radio waves being used. It is labeled with a 1 to represent radio waves.

Radio (6) Microwave (3) IR (2) Visible Light (9) UV (3) X-ray (6) Gamma (1) 1

1 Radio 1 Microwave 2 2 Infrared 3 1, 2, 3, 4,5, 6, 7 Visible Light 4 4 Ultraviolet 55 X-Ray 6 Gamma

Hubble Space Telescope Click on the Image

Chandra Click on the Image X-Ray Observatory

Spitzer Click on the Image Infrared Observatory