Electromagnetic Waves

Electromagnetic Spectrum Double Slit Experiment tour of the EM spectrum

Examples of electromagnetic waves Radiowaves Microwaves Infrared Visible light Ultraviolet X-rays Gamma

Electromagnetic waves Electromagnetic waves: vibrating electric charges that can travel through space Radiant energy: the energy carried by an electromagnetic wave

Properties of Electromagnetic Waves 1.Moves through space, solids, liquids and gases 2.Carries energy like other waves 3.All matter is in motion, all matter has charged particles, so all matter emits electromagnetic radiation 4.All electromagnetic waves travel at the speed of light (3 X 10⁸ m/s) 5.As the frequency of E.M. waves increases, the energy increases 6.As the wavelength of E.M. waves decreases, the energy increases

Light as a wave Light as a wave: light interferes, reflects, refracts and diffracts so it is a wave

Light as a Particle Light as a particle: Light is made of particles called PHOTONS Double Slit Experiment

Radiowaves Microwaves Infrared Ultraviolet X-ray Gamma Wavelength Frequency Energy

Learning Check 1.Electromagnetic waves carry _______________. 2.The speed of light is ________________. 3.Shorter wavelengths of light have _________ energy than longer wavelengths of light. 4.Explain how light is a wave and a particle. 5.How can light waves travel through empty space? 6._______________ have the least amount of energy. 7._______________ have the most energy. 8.Visible light is _______ nm to _______ nm. 9._______________ are light waves used in communications. 10.Sunburns are caused by _________ radiation.

The Electromagnetic Spectrum Nanometer: Used to measure electromagnetic frequencies (1 billionth of a meter) The electromagnetic Spectrum: the entire range of electromagnetic wave frequencies

Electromagnetic Spectrum Radiowaves: the lowest electromagnetic wave frequency with wavelengths from 1 meter to several kilometers Size: person, building, mountains Microwaves: electromagnetic waves with low frequencies and wavelengths 1-30 cm Bugs, books

Uses for radiowaves Microwaves: cook food, satellite and radio communications Radar: find the position of objects (similar to sonar) Magnetic Resonance imaging: helps us see into tissues to diagnose illness

modern marvels stealth technology

Examples of electromagnetic waves Infrared waves: electromagnetic waves with wavelengths between nm Every object emits infrared light in the form of heat Size: eye of a needle to a single celled organism Uses: Remote control, CD and DVD players, Night vision, Astronomy infrared more than our eyes can see

Visible Light Visible light: electromagnetic waves with wavelengths between 400 and 800 nm We see color because parts of our eyes react to visible light Size: microorganisms, bacteria

Ultraviolet waves Ultraviolet waves: Electromagnetic waves with wavelengths between 10 and 400 nm Small enough to enter cells and cause damage Size: virus, protein, carbohydrates

UV uses Uses for UV radiation: Sterilizing medical tools Makes objects glow florescent

X-rays X-ray waves: Electromagnetic waves with wavelengths between 1-10 nm Size: an single atom Uses: medical and dental x-rays

Gamma waves Gamma waves: electromagnetic waves with the highest frequencies and wavelengths smaller than 1 nm Most dangerous to humans Size: nucleus of an atom Uses: radiation therapy for cancer and diseases

Learning Check 1.Identify 3 objects in a home that produce electromagnetic waves and describe how the electromagnetic waves are used. 2.Radiowaves are as big as a ______________________ 3.Ultraviolet waves are as big as an ________________ 4.Visible light waves are as big as a __________________ 5.Gamma rays are as big as a __________________ 6.Electromagnetic waves we can see are called ________________. 7.Name one use for ultraviolet waves. 8.Electromagnetic waves we cannot see include: 9.Name one use for infrared waves. 10.Which electromagnetic waves have the most energy?

Radio Transmisions 1.The antenna picks up the radiowave 2.The electromagnet in the radio vibrates the electrons 3.The electrons produce a current that contains the information 4.The amplifier boosts the current and sends it to the speakers AM: poorer sound quality, cheaper, can be transmitted over longer distances FM: better sound quality, less prone to interference, can be stopped by barriers

Television Transmissions 1.Sound and picture are converted into microwaves or radiowaves 2.The waves are broadcast by different station carriers 3.Audio is sent by FM and images are sent by AM

Telephone Transmissions 1.A microphone converts sound waves into electrical current 2.The current is transmitted to cell phone towers in the form of microwaves 3.A cell phone tower constantly receives and sends messages to a base station

Communication Satellites 1.A station broadcasts a microwave signal to the satellite 2.The satellite receives the signal and amplifies it 3.The signal gets transmitted back down to a different place on Earth

GPS Global Positioning System: a system of satellites,, that can determine your exact location on Earth’s surface