Textbook pages 92-99
A disturbance that travels through a medium
Medium: a substance that carries the disturbance from one location to another
A disturbance that travels through a medium Medium: a substance that carries the disturbance from one location to another ▪ How? The particles of the medium interact with particles next to them allowing the disturbance to travel Examples of a medium Water Air Ground
Transports energy from one place to another
Particles of the medium are only temporarily displaced from the rest position
Transports energy from one place to another Particles of the medium are only temporarily displaced from the rest position ▪ Does not transport matter
Propagation Amplitude Wavelength Frequency
Waves are distinguished by the way they propagate through a medium
Transverse Waves Propagates perpendicular to the motion of the medium
Transverse Waves Equilibrium
Longitudinal Waves Propagates parallel to the motion of the medium
Longitudinal Waves Propagates parallel to the motion of the medium
Longitudinal Waves Propagates parallel to the motion of the medium
Longitudinal Waves Propagates parallel to the motion of the medium
Related to the amount of energy transferred by a wave
Transverse Waves Maximum distance travelled by a particle in the medium compared to its equilibrium position Equilibrium
Transverse Waves Depends on energy transmitted by the wave ENERGYAMPLITUDE
Longitudinal Waves How tightly the medium is pushed together at the compressions
Longitudinal Waves Depends on the density of compression DENSITYAMPLITUDE
Length of a wave’s complete cycle Transverse Waves
Length of a wave’s complete cycle Longitudinal Waves
Number of cycles per unit of time Measured in Hertz (Hz) – the number of cycles per second 1 Hz = completes one full cycle in one second
Speed of a wave depends on Medium it travels in Temperature
Speed = frequency x wavelength
v = f x v = speed (m/s) f = frequency (Hz) = wavelength (m)
What is the speed of a sound wave that has a wavelength of 2.00m and a frequency of 170.5Hz?
f = 170.5Hz = 2.00m
What is the speed of a sound wave that has a wavelength of 2.00m and a frequency of 170.5Hz? f = 170.5Hz = 2.00m v = ?
What is the speed of a sound wave that has a wavelength of 2.00m and a frequency of 170.5Hz? f = 170.5Hz = 2.00m v = ? v = f x
What is the speed of a sound wave that has a wavelength of 2.00m and a frequency of 170.5Hz? v = (170.5Hz)(2.00m) v = 341 m/s f = 170.5Hz = 2.00m v = ? v = f x
What is the speed of a sound wave that has a wavelength of 2.00m and a frequency of 170.5Hz? v = (170.5Hz)(2.00m) v = 341 m/s f = 170.5Hz = 2.00m v = ? v = f x The speed of the sound wave is 341 m/s
Mechanical Waves Electromagnetic Waves
Can only propagate in a medium
How? A disturbance changes the physical shape of the medium and passed onto neighbouring particles
Can only propagate in a medium How? A disturbance changes the physical shape of the medium and passed onto neighbouring particles Examples: water waves, sound waves, seismic waves
Can propagate in a medium and a vacuum
Carry Radiant Energy
Can propagate in a medium and a vacuum Carry Radiant Energy Examples: light waves in space
Categories of electromagnetic waves Classified by frequency and wavelength FREQUENCYENERGY
Long Low Short High
Radio Waves Smallest frequency Invisible & transport little energy Example: Radio, Television, Microwaves, Cellphones
Infrared Invisible, but feel the warmth emitted Example: Night vision goggles, short-distance communication (wireless keyboards, remote controls, etc.)
Visible Light Only electromagnetic waves that can be seen by humans Together, colours make up white light Example: Photography, movies, computer screens
Ultraviolet Rays (UV) Invisible to humans Greater frequency, transport more energy Responsible for suntans, but can cause cancer Example: sterilization of surgical instruments, treatments
X-Rays High frequency Able to travel through media opaque in visible light Example: baggage inspection, radiography
Gamma Rays Highest frequency and transports the highest energy Travel easily through matter Can cause burns, cancer, and genetic mutations Example: cancer treatment, food preservation
Read Textbook pages Do Workbook pages 49-52