What things do you do every day that depend on waves? What kind of waves do you think are involved? Agenda for Tuesday Nov 16 th 1. Waves Notes

Waves Def. – a disturbance that carries energy through matter or space – Most waves travel through a medium – Light does not require a medium

Characteristics of Waves Crest – highest point of a wave Trough – lowest point of a wave Amplitude – height of the wave Wavelength – distance between a point and an identical point on the next wave

Period and Frequency Period – time for 1 full wavelength to pass Frequency – full number of wavelengths that pass a point in a given time – Frequency = 1/t – Hertz (Hz) Light comes in a wide range of frequencies and wavelengths

Wave speed Wave speed = frequency x wavelength v = f x λ The string of a piano that produces the note middle C vibrates with a frequency of 264 Hz. If the sound waves produced by this string have a wavelength of 1.30 m, what is the speed of the sound?

Homework Read pages 463 – 471 Answer questions 1 – 9 on page 471

Draw a wave and label the crest, trough, wavelength, and amplitude Agenda for Wednesday Nov 17 th 1.Light and Sound waves 1.Practice

Sound Waves Wave that is caused by vibrations and travels through a material medium Speed of sound depends on medium

Sound Waves Loudness is determined by intensity – Higher frequency the greater intensity Depends on the amplitude and distance from the source of the waves

Sound Waves Pitch is determined by frequency – The pitch is a measure of how high or low a sound is perceived to be depending on the frequency of the sound wave – High-pitch = high-frequency = a lot of wavelengths – Low-pitch = low frequency = few wavelengths

Light Waves Energy of light is proportional to frequency

Light Waves Speed of light depends on the medium

Light Waves Brightness of light depends on intensity – Rate at which energy flows through a given area of space – High intensity = more wavelengths Intensity of sound & light decrease the further away you get

Electromagnetic Spectrum The electromagnetic spectrum consists of light at all possible energies, frequencies, and wavelengths Frequency increases as wavelength decreases Frequency decreases as wavelength increases

Lower Energy Higher Energy Waves

Electromagnetic Spectrum Sunlight contains ultraviolet light – The invisible light that lies just beyond violet light falls into the ultraviolet (UV) portion of the spectrum X rays and gamma rays are used in medicine – X rays have wavelengths less than 10 –8 m – The highest energy electromagnetic waves are gamma rays

Electromagnetic Spectrum Infrared light can be felt as warmth Infrared (IR) wavelengths are slightly longer than red light Microwaves are used in cooking and communication Microwaves have wavelengths in the range of centimeters Radio waves are used in communications and radar Radio waves have wavelengths that range from tenths of a meter to millions of meters

Order of Energy of Waves Strongest = Highest Frequency Gamma X-rays UV Visible Light Infrared Microwaves Radio Waves Weakest = Lowest Frequency

What are the strongest types of light waves? Weakest? Agenda for Thursday Nov 18 th 1.Calculating frequencies 2.Practice with Waves 3.Questions 1, 2, 4, 5 on page Questions 1-5 on page 505

What is the equation for wave speed? What are the units for wave speed, wavelength, and frequency? Agenda for Friday Nov 19 th 1.Quiz 2.Geology Video