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Waves and the Electromagnetic Spectrum Ms. Twardowski 8 Tan Dover Central Middle School
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Waves Waves are a means by which energy is transported from one region to another.
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Waves Energy is carried from one point to another through the action of invisible waves! DID YOU KNOW that invisible waves of energy are bouncing off us, passing through us, and being absorbed by your body EVERY second of EVERY day?!
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Parts of a Wave Crest – the top part of the wave. Trough – the bottom part. Wavelength – the distance from crest to crest on a wave. Frequency – how many ‘crests’ pass by a certain point per second.
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Frequency The higher the frequency number the faster the wave moves. The faster the waves moves, the more energy it carries. Some waves are dangerous and can cause cancer, damage your skin and eyes, and even cause death!
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Waves All waves have a source…the SUN! The sun transforms energy into forms that can be carried by waves. WAVES ARE NOT MATERIAL OBJECTS! You can’t touch them or see them. They have NO mass!
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Waves Waves are vibrations that transport energy. Sometimes waves need these vibrations of particle in the object to move. Some waves can travel without the need for vibrations in particles.
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Mechanical Waves There are two categories of waves. One is Mechanical. Mechanical Waves NEED particle vibrations to move energy. (Therefore, anything that is a mechanical wave would NOT work in space!) They carry KINETIC energy (KE)
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Some type of Mechanical Waves Sound waves (hearing, listening to music, etc.) –Audible waves (20Hz-20,000Hz) – waves you can hear. –Infrasonic waves (too slow to activate your hearing. Below 20Hz) –Ultrasonic waves (vibrate too fast to be heard by “humans”. Above 20,000Hz) Earthquakes and tsunamis
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Electromagnetic Waves Do NOT need particles vibrations to be transported CAN work in the empty vacuum of space! Carry ELECTRIC and MAGNETIC energy (EM)
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The Electromagnetic Spectrum There are seven (7) types of EM Waves: –Gamma rays (fastest and DANGEROUS) –X-rays –Ultraviolet (UV) radiation –Visible Light (how we see) –Infrared radiation (IR) –Microwaves –Radio waves
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Organisms and waves Animals that can hear and produce infrasonic waves: elephants, pigeons, octopus, squid, etc. Animals that can hear ultrasonic waves: bats, dogs, cats dolphins, etc. Animals that can see UV light: bees, butterflies, spiders (most mammals CANNOT see UV light). Animals that can see IR: snakes, mosquitoes, most predators.
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How important is energy transported by waves? The energy that is carried by waves is critical to life on Earth (see paper on Elmo. Lab #12, page 7).
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Review What is the source of all energy? (Answer, please!) Name the parts of a wave. Name a type of mechanical wave. Name at least 3 electromagnetic waves. Which EM waves enable us to see?
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How We Hear and How We See. Homework: Due the next time you have science. Read How We Hear and How We See. Take notes on both papers. Draw AND label parts of the ear and eye. (You can trace if you want).
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