Waves, Sound, and Light

1. Waves, Sound, and Light

2. A wave is a disturbance that moves through matter or space. They carry energy from one place to another. When waves travel through solids, liquids, and gases, matter is not carried along with the waves. Waves

3. Transverse Compressional Electromagnetic Types of Waves

4. These mechanical waves cause particles in matter to move back and forth and at right angles to the direction that the wave is travelling. Crests and troughs are part of this wave. A crest is the highest part of the wave. The trough is the lowest part of the wave. Transverse

5. Example of Transverse Waves

6. This mechanical wave causes particles of matter to move back and forth in the same direction the wave is travelling. The waves that are closest together are called compressions. The waves that are farther apart are called rarefactions. Compressional

7. Example of Compressional Wave

8. These waves are created by earthquakes. They can be compressional and transverse. The rolling waves from the earthquake are combinations of compressional and transverse waves. Seismic Waves

9. Light, radio waves, and X rays are examples of electromagnetic waves. These are transverse waves and contain electric and magnetic parts. Electromagnetic

10. Wavelength Frequency Amplitude Wave Speed Properties of Waves

11. The distance between one point on a wave and the nearest point moving with the same speed and direction is the wavelength. This can be measured from crest to crest or compression to compression. Wavelength

12. The number of wavelengths that pass a given point per second is frequency. Frequency

13. Half the distance between the crest and the trough is the amplitude. The more energy a wave carries, the higher the amplitude. Amplitude

14. The speed of a wave is determined by the medium through which it is travelling. A medium could be air, water, or a solid. Wave speed = wavelength x frequency Wave Speed

15. The Law of Reflection Refraction Diffraction Waves can Change Direction

16. The angle that an incoming wave makes with the normal equals the angle that the outgoing wave makes with the normal is the law of reflection. Reflection

17. The change in direction of a wave when it changes speed as it travels from one material to another is refraction. This happens when a wave goes from one medium to another. Refraction

18. Waves can change direction by diffraction, which causes a bending of waves around an object. The size of the object determines the amount of diffraction. Diffraction

19. Making Sound Waves Speed of Sound Loudness of Sound Frequency and Pitch Hearing and the Ear The Reflection of Sound Sound Waves

20. Sound waves are produced by vibrations, and are compressional waves. Sound waves can only travel through matter, like air, water, or solids. Sound does not travel in empty space. Making Sound Waves

21. The speed of sound is determined by the material it is travelling in. Sound waves travel faster through solids and liquids. Temperature can also affect the speed. As temperature increases, the speed increases. Speed of Sound

22. The amount of energy that a wave carries past a certain area each second is intensity of the sound. Sound with a greater amplitude has a greater intensity. The intensity is measured in units of decibels. Loudness of Sound

23. loudness

24. Frequency of sound is determined by the frequency of the vibrations that produce the sound. Frequency is measured in units called hertz, which is the number of vibrations per second. Pitch is the human perception of the frequency of sound.Sounds with low frequency have low pitch, and with high frequency, a high pitch. Frequency and Pitch

25. Frequency and Pitch

26. The ear is an organ that is used to detect sound. The outer ear is the sound collector. The middle ear is the sound amplifier. The inner ear transmits signals to the brain about the sound being heard. Hearing and the ear

27. The Ear

28. Echoes are sounds that reflect off surfaces. Repeated echoes are called reverberations. Echolocation is the process of locating objects by bouncing sounds off them. The reflection of sound

29. Waves in Empty Space Properties of Light Waves The Electromagnetic Spectrum The Eye and Seeing Light Light

30. Electromagnetic waves are waves that can travel through matter or empty space. Light travels 300,000km/s in empty space. Wavelengths of light is expressed in nanometers ( a billionth of a meter). Waves in Empty space

31. Light waves are electromagnetic waves containing electric and magnetic properties, or fields. The number of times the wave vibrates is the frequency. The intensity of light is the measure of the amount of energy the wave carries. Dim light has lower intensity. Properties of light waves

32. This is the complete range of energy arranged according to wavelength and frequency. It ranges from low energy, frequency, long wavelength, to high energy, frequency, short wavelength. The electromagnetic spectrum

33. Electromagnetic spectrum

34. The organ used for seeing is the eye. Light enters the eye through the cornea, then the lens. Reflection of the light can produce color. The back of the eye contains the retina and contains rods and cones. Cone cells allow us to see color and rods allow us to see in dim light. The eye and seeing light

35. The eye