3 The source of allwaves is somethingthat vibrates.A repeating, back-and-forth motion about an equilibrium position is a vibration.
4 Some Definitions A wave is a disturbance that propagates through space and time, usually withtransference of energy.Propagate - to move Transference - a transferA wave moves energy from one place to another.
5 All waves have Crest - Highest point on the wave troughCrest - Highest point on the waveTrough - lowest point on the waveWavelength () lambda.length from crest to crestMeasured in meters.Amplitude - height of waveMeasured in meters about the midpoint.
6 Frequency The amount of cycles per second. Measured in Hertz (Hz.) Ex. A dog wags its tail 5 times a second.Tail wags with a frequency of 5 Hz.MathWavelength times frequency = wave speed.
7 Try This! Use the math formula from the previous slide. Sound travels at 340 m/sec.A good low bass note of c# has a frequency of about 34Hz.What is the wavelength of the note?
8 Period The time it takes to move through one cycle is the period The period is the reciprocal of the frequency.They are inverselyrelated.We use the Greekletter (tau) torepresent the period.
9 The Pendulum The time of a back-and-forth swing of the pendulum is called the period.The period is measured in seconds.We use the Greek letter (tau)to represent the period
10 More about the Pendulum The period of the pendulum depends onthe length of a pendulumandthe acceleration of gravity.
11 Simple harmonic motion The back-and-forth vibratory motion (often called oscillatory motion) of a swinging pendulum is called simple harmonic motion.The pendulum is an example of simple harmonic motion.
12 Two Kinds of Waves Fundamentally, there are two types of waves. Before we get to the two kinds of waves, you need to know a word.Medium - any solid, liquid, or gas.
13 Transverse WavesWhenever the amplitude of the wave is at right angles to the direction in which a wave travels, the wave is a transverse wave.Transverse waves do not need a medium to propagate through.
14 Longitudinal WavesWhen the particles oscillate parallel to or along the direction of the wave rather than at right angles to it, the wave is a longitudinal wave.Sometimes called compression waves.Longitudinal waves need a medium to propagate through.
15 Difference between Transverse and Longitudinal Waves
16 Standing WavesWhen waves hit solid boundaries, like the walls of a room, standing waves can appear.It appears that the waves is stationary, but it is really moving in a way that makes it look like that.
17 Nodes and Antinodes Node- Place that does not move Antinode- Place of maximum displacementAntinodes are half way between nodesAnti-NodeNodeNodeAnti-NodeAnti-Node
18 Interference When two waves cross paths, they are said to interfere. This interference can be broken up into two categories.
19 Constructive or Destructive Constructive Interference- When two or more waves interfere and the resultant wave has a larger amplitude.Destructive Interference- When two or more waves interfere and the resultant wave has a smaller amplitude than the original waves.
21 Doppler EffectThe shift in frequency due to the motion of the source of waves.As a wave source approaches, an observer encounters waves with a higher frequency. As the wave source moves away, an observer encounters waves with a lower frequency.
22 Bow WavesA bow wave occurs when a wave source moves faster than the waves it produces.
24 Slinky Lab Wrap UpDescribe the amplitude of the first waves that you made. What are these waves called?Describe the amplitude of the second kind of waves that you made. What are these waves called?How are the amplitudes of the two waves different in relation to the way the waves propagate?What happened to the waves as you made the slinky tighter?
25 Summary of Tick Tock Lab Answer the following questionsDefine PeriodWhy does the mass of the pendulum fall towards the ground?What are the two things that change the period of the pendulum?What was the length of the pendulum with a period of 1 sec.?
26 Mini Quiz Get out a piece of paper. Define Transverse waveDefine Longitudinal WaveAre sound waves different than light waves?