1/14/Day 1 Introduction to Waves Homework Missing Work MP end Next Fri Wave Motion What Is a Wave? A wave is a disturbance that carries energy through matter or space. What Is a Wave? Most waves travel through a medium. medium: a physical environment in which phenomena occur Air Water - Etc mechanical wave: a wave that requires a medium through which to travel examples: sound waves, water waves What Is a Wave? Electromagnetic waves do not require a medium. electromagnetic wave: a wave that consists of oscillating electric and magnetic fields, which radiate outward at the speed of light examples: visible light waves, radio waves Electromagnetic Waves What Is a Wave?, continued Waves transfer energy. Small or Large amounts Depending on Type and Size Tsunamis carry enough energy to cause damage to coastal towns. The energy of normal ocean waves breaks up rocks into pieces to form sandy beaches. Tsunami What Is a Wave? Energy may spread out as a wave travels. When sound waves travel in air, the waves spread out in spheres. As the waves travel outward, the spherical wave fronts get bigger, so the energy spreads out over a larger volume. Vibrations and Waves How are waves generated? Most waves are caused by vibrating objects. The sound waves produced by a singer are caused by vibrating vocal cords. Electromagnetic waves may be caused by vibrating charged particles. For mechanical waves, the particles in the medium through which the wave passes vibrate, too. Transverse waves have perpendicular motion. transverse wave: a wave in which the particles of the medium move perpendicularly to the direction the wave is traveling Transverse Wave Longitudinal waves have parallel motion. longitudinal wave: a wave in which the particles of the medium vibrate parallel to the direction of wave motion Longitudinal Wave Waves have crests and troughs or compressions and rarefactions. crest: the highest point of a wave trough: the lowest point of a wave compressions: the crowded areas of a longitudinal wave rarefactions: the stretched- out areas of a longitudinal wave Surface Waves The particles in a surface wave move both perpendicularly and parallel to the direction in which the wave travels. surface waves: waves that occur at the boundary between two different mediums, such as water and air Formation and Movement of Ocean Waves Amplitude amplitude: the maximum distance that the particles of a waves medium vibrate from their rest position for a transverse wave, measured from the rest position to the crest or the trough expressed in the SI unit meters (m) Wavelength wavelength: the distance from any point on a wave to an identical point on the next wave for a transverse wave, measured from crest to crest or trough to trough represented by the symbol expressed in the SI unit meters (m) Amplitude and wavelength tell you about energy. larger amplitude = more energy shorter wavelength = more energy