What is a wave? A periodic disturbance in a solid, liquid, or gas as energy is transmitted through a medium What is a medium? A physical environment in which phenomena occur (substance through which a wave can travel

2 types of waves Transverse and longitudinal Transverse-wave in which the particle of the medium move perpendicularly to the direction the wave is traveling Longitudinal-wave in which particles of the medium vibrate parallel to the direction of wave motion

Parts of transverse wave: Crest-highest point on transverse wave Trough-lowest point between each crest Amplitude-maximum distance that the particles of a wave’s medium vibrate from their rest position Wavelength-distance from any point on a wave to an identical point on the next

Draw picture and label transverse wave

Write 3 things you learned about transverse waves today

Parts of longitudinal wave Compressions –part of wave where particles are crowded Rarefaction-part of wave where particles are spread apart Wavelength-same as transverse (compression to compression or rarefaction to rarefaction)

Properties of Waves Larger amplitude = more energy You must work harder to make a wave with higher crests Shorter wavelength = More energy Shorter wavelength means crests are closer Higher frequency = more energy Frequency is the number of waves produced in a given amount of time

Electromagnetic Waves Electromagnetic waves do not need a medium All electromagnetic waves are transverse waves Examples: Visible light Microwave ovens TV signals Radio signals X rays

Mechanical Waves -Waves that need a medium are called mechanical waves. -In mechanical waves, when a particle vibrates, it pass energy to the next particle which passes energy to the next. Examples of mechanical waves: -sound waves (longitudinal wave) -ocean waves -seismic waves What is the medium for each of these examples?

Wave Speed Speed at which a wave travels V = λ x f V=wave speed λ =wavelength F=frequency