waves, sound, electromagnetic radiation

Waves, sound, Electromagnetic Radiation

Conceptual Physics

To do… See how many of the quiz topics you

can answer as a table group (if you don’t know the answer right away, seek

out the answer with your notes/webquests/EM poster)

Identify which questions your table can’t answer

Pick your top 2 topics that you need to review today…

Self-grade… Go over answers on your webquests 18 pts each answer

Shows example of a wave (indicating change in wavelengths)

2

Arrows showing areas of higher and lower wavelengths, frequencies and energy.

6

The six types of EM Waves discussed in class

6

Drawings/pictures that represent the type of wave

6

Accurate ratios and division of page 2

Creative/Artistic/Colorful/Neat/Professional 5

Totals /27

4 square notes 5 pts each page Definition = 1 Real world ex = 2 Picture = 1 3-5 facts = 2

Total = 30 pts

Radio Infrared Visible light Uv X-rays Gamma rays

Next 10 minutes Interactive review

Do NOT write for next 10 minutes

Stop – share with table group all the information you think is important for quiz, what information was clarified for you

Wave Basics

Key Vocab.-Amplitude: The maximum displacement of a wave from equillibrium (height of a wave)-Wavelength: The length of one full wave cycle or repetition -Period: The amount of time it takes a wave to complete one full cycle-Frequency: The number of wave vibrations/repetitions per second (Hz)-Equilibrium: The resting place of a wave with no disturbance-Crest: The highest point or peak of a wave-Trough: The lowest point or bottom of a wave

Crest

Trough

Line of Equilibrium

Basics Waves- traveling disturbance that

carries energy (not matter) Boat/wave example

Energy = ability to do work Vibration: any movement follows

same path repeatedly Ear drum, drum, earthquake

Vibrate – particle moving – produces energy – transfers energy to nearby particles – wave Ocean, ropes, sound, microwaves

?

?

Waves… a reviewMost waves are either

longitudinal or transverse.Sound waves are longitudinal.But all electromagnetic waves

are transverse…

Wave Types A wave is a traveling disturbance that transfers energy. 2 Types of Waves:

Transverse: side to side wave sending vibration perpendicular to the medium

Longitudinal: push & pull wave sending vibration parallel to the medium

Parallel Vibration

Perpendicular Vibration

Direction of Energy

Direction of Energy

Amplitude = amount of energy Frequency = number of waves in

given time (Hz – 1 Hz=1 wave/sec)

Speed of wave Speed = freq x wavelength (λ)

Depends on medium its traveling in Density (moves slower) – more inertia Elasticity (faster) – faster in solid than liquid/gas temperature

Write these notes down…

Key Vocab for Wave interactions Reflection – bouncing back of a wave

after it strikes a boundary that does not absorb all the wave’s energy Ray is a line drawn to show direction of a wave

and show wave activity Incident – incoming wave Reflected wave – wave being bounced back

Refraction – bending of waves due to a change in speed (occurs because waves move at different speeds in different mediums) – air to water, glass to air

Diffraction – bending of waves around the edge of an obstacle

The amount of diffraction depends on the wave length and the size of obstacle

Snowball vs. yelling

Interference – When 2 or more waves arrive at the same place at the same time – they combine to form a single wave Constructive = combine (larger amplitude) Destructive = cancel (no wave)

What wave interaction is happening to the spoon in the water?

What type of wave interaction is this?

Car headlights with open eyes

Car headlights with squinted eyelashes

What type of wave interaction is this?

What type of wave interaction is this?

What type of wave interaction is this?

What type of wave interaction is this?

What type of wave interaction is this?

http://media.pearsoncmg.com/aw/aw_0media_physics/hewittvideos/doppler.html

As a table Summarize what the doppler effect is Be ready to share

Doppler Apparent change in pitch caused by

motion As moving towards me, pitch is

higher As moving away from me, pitch is

lower

Electromagnetic Spectrum

Wavelength and the Spectrum

Electromagnetic waves Produced by the movement of

electrically charged particles Can travel in a “vacuum” (they do

NOT need a medium Travel at the speed of

light Also known as EM waves

Radio waves Longest wavelength EM waves Uses:

TV broadcasting AM and FM broadcast radio Avalanche beacons Heart rate monitors Cell phone communication

Microwaves Wavelengths from 1 mm- 1 m Uses:

Microwave ovens Bluetooth headsets Broadband Wireless Internet Radar GPS

Infrared Radiation Wavelengths in between microwaves

and visible light Uses:

Night vision goggles Remote controls Heat-seeking missiles

Visible light Only type of EM wave able to be

detected by the human eye Violet is the highest frequency light Red light is the lowest frequency

light

Ultraviolet Shorter wavelengths than visible

light Uses:

Black lights Sterilizing medical equipment Water disinfection Security images on money

Ultraviolet (cont.)UVA UVB and UVC

Energy Highest of UV waves

Lower than UVA

Health risks

Extremely low risk for DNA damage Can destroy Vitamin A in skin

Can cause DNA damage, leading to skin cancer Responsible for sunburn

X-rays Tiny wavelength, high

energy waves Uses:

Medical imaging Airport security Inspecting industrial welds

Gamma Rays Smallest wavelengths, highest

energy EM waves Uses

Food irradiation Cancer treatment Treating wood flooring

Image credits1. http://www.antonine-education.co.uk/New_items/MUS/images/M

aking6.gif2. http://www.geocities.com/researchtriangle/campus/6791/einstei

n12.jpg3. http://abyss.uoregon.edu/~js/glossary/wave_particle.html4. http://www.astro.princeton.edu/~gk/A402/electromagnetic_spec

trum.jpg5. http://science.hq.nasa.gov/kids/imagers/ems/radio.html6. http://www.nentjes.info/Palace/radio-6.gif7. http://www.mobilewhack.com/motorola-h12-bluetooth-headset.j

pg8. http://www.stuffintheair.com/radar-real-time-weather.html9. http://www.imaging1.com/gallery/images/AV%20Night%20vision

%20goggles.jpg10. http://www.global-b2b-network.com/direct/dbimage/50329753/S

tudy_Remote_Control.jpg11. http://www.georgiaprismaward.com/The_Prism_Story_files/PRIS

M%20brand%20imagemed.jpg12. http://science.hq.nasa.gov/kids/imagers/ems/uv.html

Image Credits13. http://farm3.static.flickr.com/2385/2381723771_12548f4b

d1.jpg?v=121742987914. http://intamod.com.au/images/uv2.JPG15. http://science.hq.nasa.gov/kids/imagers/ems/xrays.html16. http://www.sciencelearn.org.nz/var/sciencelearn/storage/

images/contexts/see_through_body/sci_media/neck_x_ray/17945-5-eng-NZ/neck_x_ray_full_size_portrait.jpg

17. http://www.epinion.eu/wordpress/wp-content/uploads/2008/05/airport-security1.jpg

18. http://science.hq.nasa.gov/kids/imagers/ems/gamma.html19. http://www.aboutnuclear.org/print.cgi?fC=Food20. http://www.roswellpark.org/files/1_2_1/brain_spinal/

gamma%20knife%204c.jpg