Waves

WavesUnit 3, Chapter 93-1: Types of waves:Waves carry energy away from its source in any direction.The vibrations cause waves to form in a material or medium. (M.K.)The waves pass energy on to near by particles and the process continues. (M.I.)

Mediums can be solids, liquids, or gases and are materials that are needed for some waves to move through.Waves that need a medium are called mechanical waves.If the mediums are removed, the waves stop. (M.K.)

There are two types of mechanical waves. Transverse waves move in an up and down motion.Longitudinal waves the particles of the medium vibrate back and forth along the path that the wave moves.

Longitudinal and transverse waves will form surface waves.Surface waves happen when waves form at or near the boundary between two media. (M.K.)Particles in a surface wave are really moving in a circle. (M.K.)

Electromagnetic waves do not need a medium to travel through.Electromagnetic radiation is the type of radiation associated with an electric and magnetic field.Radiation is the transfer of energy as electromagnetic waves.It can be used to cook food, treat diseases and provide energy.

3-2 Properties of wavesAmplitude is the maximum distance that the particles of the medium vibrate from their rest position.The larger the waves the more energy it takes to create them. (M.K.)A larger wave will also contain more energy than smaller ones. (M.K.)

A wavelength is the distance between any two crests or compressions next to each other in a wave.Shorter wave lengths mean that there is more energy. (M.K)Frequency is the number of waves produced in a given amount of time.Usually the time is one second.Frequency is expressed in hertz.Wave speed is the speed at which a wave travels.The formula is the wavelength times the frequency.If you increase the wave frequency, you decrease the wave length. (M.K.)Different types of media effect the waves in different ways. (M.K.)Light travels much faster through air than through glass.

3-3 Wave Interactions.Reflection happens when a wave bounces back after hitting a barrier.All waves can be reflected.Waves can be transmitted through a substance when it passes through the substance.

Refraction is the bending of a wave as the wave passes at an angle from one medium to another.When the wave moves from one medium to another the speed of the wave will change. (M.K.)A prism is a piece of glass that has polished flat sides at an angle with each other.When light passes through it will separate out into different colors.

Diffraction is the bending of waves around a barrier or through an opening.Sound waves are the best example of diffraction because of their long wavelengths and the ability to go around corners.

Interference is the result of two or more waves overlapping.Constructive interference happens when the crest of one wave overlap the crest of one or more waves and the energy of each wave combines. Destructive interference happens when the crest on one wave and the trough of another wave overlaps and the amplitude of the combined waves is smaller.

A standing wave is a pattern of vibration that simulates a wave that is standing still.The frequency at which standing waves are made is called resonant frequency.Resonance is when two objects naturally vibrate at the same frequency.