Waves of the Electromagnetic Spectrum Waves and Light Table of Contents 9.1 Waves of the Electromagnetic Spectrum Ms. De Los Rios 7th

Vocabulary 9.1 Electromagnetic Wave- A wave made up of a combination of changing electric field and a changing field. A wave that can transfer electric and magnetic energy through the vacuum of space. Electromagnetic Radiation- The energy transferred through space by electromagnetic waves. electromagnetic spectrum- The complete range of electromagnetic waves placed in order of increasing frequency. radio waves- Electromagnetic waves with the longest wavelength and lowest frequencies. Microwaves- Electromagnetic waves that have a shorter wavelength and higher frequencies that radio waves. Radar- A system that uses reflected radio waves to detect objects and measure their distance and speed. Infrared Rays- Electromagnetic waves with shorter wavelength and higher frequencies than microwaves.

Vocabulary 9.1 Thermogram- An image that shows regions of different temperatures in different colors. Visible light- Electromagnetic radiation that can be seen with the unaided eye. Ultraviolet Rays- Electromagnetic waves with wavelength shorter than visible light but longer than X-rays. X-rays- Electromagnetic waves with wavelengths shorter than ultraviolet rays but longer than gamma rays. Gamma rays- Electromagnetic waves with the shortest wavelengths and highest frequencies. Prefix thermo= Greek word thermos means “warm or hot”

Characteristics of Electromagnetic Waves pg. 315 The sun’s energy reaches Earth in the form of electromagnetic waves (E.W.) An electromagnetic wave is made up of vibrating electric and magnetic fields that move through space or some medium at the speed of light. The energy transferred by electromagnetic waves through space or matter is called electromagnetic radiation. E. W. do NOT require a medium such as air, they travel through empty space.

Waves of the Electromagnetic Spectrum pg. 315 Electromagnetic Wave An electromagnetic wave travels through space at the speed of light—about 300,000 kilometers per second.

How Do Electromagnetic Waves Compare? pg. 316 E.W. have different: Wavelengths- Is the distance between the crest of one wave and the crest of the next wave. Frequency- Is the number of waves that pass a given point in a certain amount of time. The frequency of a wave determines how much energy the wave has.

How Do Electromagnetic Waves Compare? pg. 316 A vacuum is a space that contains no air or gas. All electromagnetic waves travel at the same speed in a vacuum. All electromagnetic waves have different wavelengths different frequencies. For waves in any medium, as the wavelength decreases, the frequency increases. The higher the frequency of a wave, the higher its energy.

Important Information pg.316 Each E.W. has properties that make it useful for some purposes than others. Visible light is the only range of wavelength that your eyes can see. E. W. do NOT require a medium such as air, they travel through empty space. Long wavelength= Low frequency= Low energy (L, L,L) Short wavelength=High frequency= High energy (S,H,H) Example: Ocean waves

Important Information pg.316 We know about these waves from the sun through observation-NOT experiment. A spectrograph can be used to show the sun’s radiation include all these different types of waves.

Comparing Electromagnetic Waves Waves of the Electromagnetic Spectrum pg. 316 Comparing Electromagnetic Waves Different types of electromagnetic waves have different wavelengths. Which are the visible light, radio waves, and X-rays?

What Makes up the Electromagnetic Spectrum? pg. 317 There are many different types of electromagnetic waves. The electromagnetic spectrum is made up of:

Mnemonic Device to Memorize the Electromagnetic Spectrum Geniuses eXpect Ultraviolet Light In My Rainbow Gamma radiation X-ray radiation Ultraviolet radiation visible radiation (Light) Infra-red radiation Microwave radiation Radio waves

How Do Electromagnetic Waves Compare? pg. 317 Radio Waves (L,L,L) E.W. with the longest wavelengths(distance crest to crest) and the lowest frequencies (# of waves that pass at a certain point in a given time) They are used in broadcasting to carry signals for radio programs. Broadcasting stations sends out certain frequencies radio picks up waves, converts them into electrical signal converted into sound.

The Electromagnetic Spectrum Waves of the Electromagnetic Spectrum pg. 317 The Electromagnetic Spectrum The electromagnetic spectrum can be broken up into different categories. Use the word bank to complete the boxes in the diagram.

How Do Electromagnetic Waves Compare? pg. 318 Microwaves (S,H,H) have shorter wavelengths(crest) and higher frequencies(#) than radio waves. Microwaves have many uses, including cellular phone and radar, a system that uses reflected microwaves to detect objects and measure their distance and speed.

What Makes Up the Electromagnetic Spectrum?pg. 318 Infrared rays (S,H,H) They have wavelengths shorter than those of microwaves. The invisible heat you feel from stove is infrared radiation. Because you feel the energy of infrared rays as heat is called heat rays. Warmer objects give off infrared rays with more Energy and higher frequencies than cooler objects. An infrared camera uses infrared rays instead of light to take a picture called a thermogram that shows regions of different temperatures in different colors. Thermogram

What Makes Up the Electromagnetic Spectrum? pg. 318 Visible Light (S,H,H) These electromagnetic waves you can see. Visible light waves have shorter wavelengths and higher frequencies than infrared rays. Visible light appears white, but is a mixture of many colors. Light waves bend or refract when they enter a new medium. When light passes through rain= RAINBOW How does a prism separate colors?

Mnemonic Device to Memorize the Visible Light Spectrum ROY G BIV R: red O: orange Y: yellow G: green B: blue I: indigo V: violet

What Makes Up the Electromagnetic Spectrum? Ultraviolet rays (S, H, H) Electromagnetic waves with wavelengths just shorter than those of visible light are called UV. Too much exposure to U.V. can damage or kill living cells. Its found naturally in sunlight. We cannot see it but we can feel it, our body responds to it by turning darker. Small doses of UV rays are useful, for example, cause skin cells to produce vitamin D (Bones & teeth) UV radiation is used in sun beds & fluorescents light

What Makes Up the Electromagnetic Spectrum? X-rays (S, H, H) Electromagnetic waves with wavelengths just shorter than those of ultraviolet rays are called X-rays. Because of their high frequencies, X-rays carry enough energy to penetrate most matter. X-rays pass through soft skin and tissue but not Dense matter, such as bone or metal. Bones absorbs X-rays so they do not pass through. Therefore, X-rays are used to make images of bones and teeth. Too much exposure to x-rays can cause cancer. X-rays can be used for in industry and engineering—x-ray structures to find cracks or damage.

What Makes Up the Electromagnetic Spectrum? Gamma rays (S,H,H) Electromagnetic waves with the shortest wavelengths and highest frequencies are called G.R. Since they have the greatest amount of energy, G.R. are the most penetrating of electromagnetic waves. G.R. pass through soft skin and tissue, some of it is absorbed by cells. They are used to examine the body’s internal structures, sterilize surgical instruments, and to kill harmful bacteria in food. G.R. can also be used to target and kill cancer cells. Exposure to G.R. is dangerous, as it can make cells cancerous.

What Makes Up the Electromagnetic Spectrum? The Environmental Protection Agency of the United States tracks ultraviolet light levels in Texas and throughout the country. The agency’s UV index rates ultraviolet exposure on a scale of 1 to 11+. High ratings result in UV exposure warnings. These warnings let people know how long they can be out in the sun safely without sunblock.

Example of Electromagnetic Waves

The electromagnetic spectrum includes many kinds Waves of the Electromagnetic Spectrum Types of Waves The electromagnetic spectrum includes many kinds of waves. Identify each kind of wave on the electromagnetic spectrum. What is the name of the highest energy waves?

Online resources http://www.bbc.co.uk/schools/gcsebitesize/science/aqa_pre_2011/radiation/anintroductiontowavesact.shtml BBC Waves Activity The electromagnetic spectrum activity Electromagnetic Spectrum NASA Examine the sun at different wavelengths Frequency & Wavelength Activity Brainpop Waves Brainpop Electromagnetic Waves Brainpop Color Brainpop Rainbow Brainpop Light http://sammyholmes.wikispaces.com/Wave+Interactions http://app.discoveryeducation.com/player/?assetGuid=0bbc28bf-4861-4601-8a36-b3576ecee9ab&fromMyDe=0&isPrinterFriendly=0&provider=&isLessonFromHealth=0&productcode=DSC&isAssigned=false&includeHeader=YES&homeworkGuid=