Oscillation of a system to a preferential frequency causing the system to achieve a greater amplitude then its oscillation. Oscillation of a system to a preferential frequency causing the system to achieve a greater amplitude then its oscillation.

Swing set Swing set Lasers Lasers

With your group come and grab a slinky and vibrate it at different frequencies. Notice what happens at the resonant frequency and if you vibrate at slightly slower and higher frequencies. With your group come and grab a slinky and vibrate it at different frequencies. Notice what happens at the resonant frequency and if you vibrate at slightly slower and higher frequencies.

Resonance happens in nature frequently. Music, watches, electrons. However, one disastrous effect of not taking resonance into account is the Tacoma Narrows Bridge. Resonance happens in nature frequently. Music, watches, electrons. However, one disastrous effect of not taking resonance into account is the Tacoma Narrows Bridge.

Now we will try the Doppler effect with both observer and source moving. Now we will try the Doppler effect with both observer and source moving.

A car is emitting a sound of 20 hz. If it is moving towards you at 20 m/s and you are moving away from the source at 10 m/s what is the perceived frequency you hear? A car is emitting a sound of 20 hz. If it is moving towards you at 20 m/s and you are moving away from the source at 10 m/s what is the perceived frequency you hear?

Sound can resonate in open and closed tubes to give us different frequencies for our sound to resonate at. Sound can resonate in open and closed tubes to give us different frequencies for our sound to resonate at. Much like musical instruments, these frequencies are determined by the length of our tube. Much like musical instruments, these frequencies are determined by the length of our tube.

The sound pressure wave has to have an area of low and high pressure demonstrated by our anti node. With regular pressure being at the node The sound pressure wave has to have an area of low and high pressure demonstrated by our anti node. With regular pressure being at the node See board for node anti node behavior See board for node anti node behavior

In an open tube We get an area of high and low pressure inside our tube but will stay at an even pressure at the ends. In an open tube We get an area of high and low pressure inside our tube but will stay at an even pressure at the ends. See board for node antinodes behavior See board for node antinodes behavior

An open pipe has a length of 10m. What is the pipes 1 st, 3 rd, and fifth, harmonic frequencies? An open pipe has a length of 10m. What is the pipes 1 st, 3 rd, and fifth, harmonic frequencies? A closed pipe has a length of 5 m, What is the pipes 1 st, 3 rd, and fifth, harmonic frequencies? A closed pipe has a length of 5 m, What is the pipes 1 st, 3 rd, and fifth, harmonic frequencies?

We have learned about sound waves, but today we will learn how to practically apply that knowledge to music We have learned about sound waves, but today we will learn how to practically apply that knowledge to music

As you can see our tuning fork creates a perfect sinusoidal wave. However all fundamental frequencies don’t work like that. As you can see our tuning fork creates a perfect sinusoidal wave. However all fundamental frequencies don’t work like that. Instruments use the principal of superposition to create pleasant sounding music. The difference between these complex waves is called timbre Instruments use the principal of superposition to create pleasant sounding music. The difference between these complex waves is called timbre

Using what we learned about fundamental frequencies we can find the fundamental frequencies of guitars, violins, and other string instruments Using what we learned about fundamental frequencies we can find the fundamental frequencies of guitars, violins, and other string instruments However, Velocity of our wave is determined by many different things. However, Velocity of our wave is determined by many different things.

Wind instruments turn vibrations from your mouth and use resonance to create vibrations which travel through the instrument to produce a larger amplitude. Wind instruments turn vibrations from your mouth and use resonance to create vibrations which travel through the instrument to produce a larger amplitude. These instruments use the open and closed pipe ideas except more complex due to the different configurations of your fingers. These instruments use the open and closed pipe ideas except more complex due to the different configurations of your fingers.

When two notes are played that sound pleasant, we call that consonance. Pythagoras experimented with this idea and found the best sounding combonations are in ratios. 1:2, 2:3, 3::4 and so on. When two notes are played that sound pleasant, we call that consonance. Pythagoras experimented with this idea and found the best sounding combonations are in ratios. 1:2, 2:3, 3::4 and so on.

Octaves are created when two frequencies are in a 1:2 ratio Octaves are created when two frequencies are in a 1:2 ratio For a frequency of 440hz our next higher octave is 880hz. For a frequency of 440hz our next higher octave is 880hz. Another common ratio is 4:5 called the major third Another common ratio is 4:5 called the major third