light waves are called electromagnetic waves These waves carry energy  Light is made of photons  Photons carry energy  Energy = radiation  A wave of light and a ray of light are the same

Parts of a Light Wave All waves carry energy A = the height of the wave = brightness of the light λ = wavelength = length of one wave measured from crest to crest or trough to trough f = frequency = speed of the wave or the number of waves that pass per second

Relationship to energy Low frequency High frequency

The Electromagnetic Spectrum – describes all of the different types of light that exist: radio, microwave, infrared, visible, ultraviolet, x-ray, and gamma  Which wave carries the highest amount of energy?  Which wave carries the least amount of energy?

For each part of the spectrum you need to know the following information:  Size of the wavelength  Objects that naturally produce this type of light  How the light interacts with humans

Gamma Rays The wavelength size :  Objects that produce gamma rays:  supernova explosions, neutron stars, and black holes  Interaction with humans - used to:  sterilize surgical instruments  kill harmful bacteria in food  kill cancer cells (cm) This is the size of an

Gamma Rays (m) Cool Info – what the sky would look like if you could see gamma photons a_rays.htmlhttp://imagine.gsfc.nasa.gov/docs/features/movies/gamm a_rays.html (open the website and click on the purple picture and make the video full screen) a_rays.html

X-Rays The wavelength size :  Objects that produce X-rays:  black holes, neutron stars, binary star systems, supernova remnants, stars, the Sun, and even some comets  Interaction with humans - X-rays pass through skin and soft tissue, but not through bone or metal.  used to produce photographs of bones to check for damage such as fractures.  also used in industry to check metal for cracks or other damage. (cm) This is the size of an

X-rays – cool facts  Discovered in Germany 1895 by Wilhelm Conrad Roentgen  He named them ` X ` rays because he did not know where the rays were coming from.  His first image was of his wife‘s hand (shown to the left)

Ultraviolet light The wavelength size :  Objects that produce ultraviolet light:  the Sun and other stars  Interaction with humans  sun beds  security pens that airport officials use to check passports  fluorescent lights (phosphor coatings inside the bulb absorb the ultraviolet light and re-emit it as visible light) (cm) This is the size of a

Ultraviolet – cool facts beneficial harmful  We need UV light to make Vitamin D  Vitamin D is important in making strong bones, a healthy immune system, and in making cells.  The energy from ultraviolet radiation can damage the molecules in your skin and even your DNA.  When you have a sunburn proteins in the blood make your blood vessels larger– this is why your skin turns red (Sobell 2001).  COOL – bees, butterflies, and other animals can see UV light: to them the sky appears purple and flowers appear different colors (see picture – what we see and what bees see)

Visible Light The wavelength size :  Objects that produce Visible light:  You (a very small amount), sun and other stars, light bulbs  Interaction with humans –  This is the only type of light we can see with our eyes (cm) This is the size of an

Visible Light White light is made of 6 different colors: RedOrangeYellowGreenBluePurple Each color carries a different amount of energy – which color would carry the most energy? The least amount of energy?

Infrared light: heat energy The wavelength size :  Objects that produce Visible light:  You and other animals, sun and other stars, light bulbs  Interaction with humans – used in  security lights  burglar alarms  remote controls for television sets and DVD player  data links over short distances between computers or mobile phones (cm) This is the size of an

Infrared: cool facts This is the main light we and other animals produce – this is the heat you feel coming off your cheeks

Microwave The wavelength size :  Objects that produce microwave light:  stars  Interaction with humans –  Cooking food – the radiation vibrates the molecules in the food to heat up the food  Use to learn about the weather  Used to transfer information :  Bluetooth  Wifi  Cell phones  Microwave ovens (cm) This is the size of an

Microwave radiation is everywhere in the universe it is left over radiation from the BIG BANG  Background-Radiation (play video) Background-Radiation Background-Radiation The view of the microwave radiation in the universe around us

Radio The wavelength size :  Objects that produce microwave light:  planets and comets, giant clouds of gas and dust, and stars and galaxies  Interaction with humans – To transfer information to and from  Radio and television stations  Wifi  Computers  Cell phones (cm)

Radio emissions from space  Radio is a type of light that we use to make sound: radio waves and changed into sound waves (see illustration below) Radio signals from stars, pulsars, black holes and other objects in space produce radio waves. We change these signals into sound waves that we can hear.  /index.html (click on this link and then click on 2-3 different sources) /index.html

Questions for objective 3  Describe what all of the waves have in common.  Describe the 3 main differences between the waves. Finish Questions from objective 2 (oage 11)

Video  If there is time watch the video:  Vl-8 Vl-8

Sources  "Gamma Rays." - Mission:Science. NASA, n.d. Web. 07 Oct  Nelson, Brent. Ask the Experts. Physicslink.com, n.d. Web. 7 Oct  Plait, Phil. "Bananas | Bad Astronomy | Discover Magazine." Bananas | Bad Astronomy | Discover Magazine. N.p., 21 Mar Web. 07 Oct  Sobell, Jeffrey M. "What Happens When You Get a Sunburn?: Scientific American." What Happens When You Get a Sunburn?: Scientific American. Scientific American, 6 Aug Web. 07 Oct  electromagnetic_spectrumrev4.shtml electromagnetic_spectrumrev4.shtml    electromagnetic-spectrum.html#lesson (login) electromagnetic-spectrum.html#lesson More space sounds  