1. Light and Sound energy

2. Wave Definition A wave – is something that carries energy though matter or space. Waves transfer energy Energy spreads out as waves move Most waves are caused by vibrating objects A medium – is the matter that waves move through Ex: water, air, space, even the earth can be a medium

3. Types of Waves Mechanical Waves – waves that require a medium to travel through Examples: ocean waves and earthquakes Electromagnetic Waves- do not require a medium to travel through and consists of moving electric and magnetic fields traveling outward toward the speed of light Examples: Light, magnetic force, radio waves

4. Transverse Waves Transverse waves- move particles up and down, perpendicular to the wave motion Crest – top of the wave Trough- bottom of the wave Wavelength- distance from crest to crest or trough to trough Amplitude- the distance from crest or trough to the starting point of the wave Frequency – the number of wavelengths in a given time Period – the time is takes to complete a wave cycle

5. Examples of Transverse Waves Light, stringed instruments, radio waves, microwaves, heat waves Red- longer slow wavelengths Purple – short fast wavelengths

6. Longitudinal Waves Longitudinal Waves- particles move parallel to the direction of the wave Compression- “squished” part of the wave (compressed ) Rarefaction – stretched part of the wave Wavelength – distance from compression to compression or rarefaction to rarefaction

7. Examples of Longitudinal Waves Sound, some earthquakes, deep water waves

8. Surface Waves Surface waves- are water waves that are both transverse and longitudinal waves Surface waves cause objects to move in a circular motion on the surface

9. Formulas Wave speed = wavelength X frequency Wavelength = speed frequency Frequency = speed wavelength

10. Ways Waves Interact Reflection Refraction Diffraction Interference Constructive Destructive Standing Waves

11. Reflection When an object or wave hits a surface through which it cannot pass, it bounces back. Angle of incidence Angle of reflection

12. Examples of reflection Mirror Echo Ball against a wall

13. Refraction is when a wave moves from one medium into another medium at an angle, it changes speed as it enters the second medium which causes it to bend. The bending of waves due to a change in speed is called refraction.

14. Refraction Though all waves change speed when they enter a new medium. Bending occurs when one side of the wave enters the new medium before the other side

15. Diffraction When a wave passes a barrier or moves through a hole in a barrier it bends and spreads out.

16. Interference Constructive interference occurs whenever two waves combine to make a wave with a larger amplitude. Destructive interference when the amplitudes of two waves combine producing a smaller amplitude.

17. Standing waves: If the incoming wave and the reflected wave combine at the right places the combined wave appears to be standing still. It appears to be standing in one place, even though it is two waves interfering as they pass through each other.

19. Nodes and Antinodes node: at certain points, destructive interference causes the two waves to combine and produce an amplitude of zero. Antinode are the points of maximum energy. The crests and troughs of a standing wave.

20. Resonance Most objects have a natural frequency of vibration. Resonance occurs when vibrations traveling through an object match the object’s natural frequency. An object that is vibrating at its natural frequency absorbs energy from the objects that vibrate at the same frequency. Occurs in music.