Behavior of Waves Ms Allen Henderson Middle School

Behavior of Waves Ms. Allen Henderson Middle School 2018 - 2019

Waves • A wave is a disturbance that carries energy through matter or space. • Medium – the environment that the wave travels in (ex: water, air)

Energy of Waves • These two waves will sound the same except the high energy wave will be louder.

Wave Speed The speed of a wave will depend on the medium it travels through • The state of matter determines the speed of the wave. • Ex: In gases the particles are spread out so the wave travels slower in gases • Ex: In liquids, the particles are closer together so the energy is transferred quicker between particles of that medium • Ex: In solids, the particles are tightly packed together so the wave travels very quickly through solids

Wave Behaviors • Refraction • Absorption • Reflection • Diffraction • Interference

Reflection • Occurs when a wave strikes a surface or object and bounces back. • If the surface is flat, the angle at which the wave hits the surface will be the same as the angle at which it leaves the surface (angle in = angle out). • This is the law of reflection.

Law of Reflection • Reflection – wave strikes a surface and is bounced back. • Law of Reflection: angle of incidence = angle of reflection • An incident ray of light hits a smooth surface at an angle and is reflected back off it. • So, if a wave hits a flat surface at an angle of 36°, it will be reflected at the same angle (36°).

Examples of Wave Reflection

Refraction • Waves can bend. • This happens when a wave enters a new medium and its SPEED CHANGES. • The amount of bending depends on the medium it is entering.

Example of Wave Refraction

Diffraction • The bending of waves AROUND an object. • The amount of bending depends on the size of the obstacle and the size of the waves.

Examples of Wave Diffraction

Absorption • Absorption is when a wave comes into contact with a medium and causes the medium's molecules to vibrate and move. • One example of absorption is black pavement which absorbs energy from light. The black pavement becomes hot from absorbing the light waves.

Example of Wave Absorption

Absorption of Waves

Interference • When one wave comes into contact with another wave this is called interference. When the waves meet the resulting wave will have the amplitude of the sum of the two interfering waves.

Constructive Interference • Occurs when two waves meet and produce a larger wave.

Examples of Constructive Interference

Destructive Interference • Occurs when two waves meet and make a smaller wave or cancel each other out.

Example of Destructive Interference

Sources • www. pleasanthillschools. com/. . . /Physical%20 Science%20 Chapt er%2010 • https: //www. teachengineering. org/. . . waves. . . /clem_waves_lesso n 02_presentation. ppt • www. warrencountyschools. org/. . . /frequency_energy_and%20 w avelength. pptx? id. . • www. crosbyisd. org/cms/lib 6/. . . /334/Reflection__Refraction__an d_Diffraction. pp • http: //www. lhschools. org/Downloads/Wave%20 Properties%20 a nd%20 Wave%20 Interactions. ppt