Week 5
Resonance and Earthquake Projects
Waves carry the energy created by movements in the crust called earthquakes. We can calculate that energy and the speed at which it travels. This information can help us to develop early warning systems by identifying dangerous quakes and alerting people to their projected time of arrival.
Day 1
Notice the movement of the table in this video. Think back to forces and Newton's Laws of Motion. Think about net force. Think about how forces are carried as energy in waves and how the table interacts with the metronomes.Â
In the video, notice that the first wave train that comes toward you in the tank has a much smaller amplitude than when the wave is returned via reflection. The reflecting wave passes the incident wave at the same frequency. Crests and troughs line up and boost the amplitude of the waves.Â
 In the this video a wine glass with a natural resonant frequency is flexed by an incident sound wave. When the professor chooses the frequency that best matches the natural frequency of the glass it gives the edge of the glass a push at the right time like pushing a child on a swing. The oscillation amplitude increases until the glass shatters. Â
This online tone generator can be used to find the resonant frequency of common objects or structural components. Experiment with different frequencies at different amplitudes. Caution: May cause items to move or break.
Mathematics of standing waves and harmonic wave patterns
In the above video an engineer shows how machines can fatigue and break due to harmonic resonance. Pay close attention to the nodes and antinodes and how he suggests bracing a machine to reduces damage from resonance.Â
Crest - The highest point on the wave.
Trough - The lowest point on the wave.
Wavelength or Cycle - The horizontal distance between successive crests or troughs. The distance from one point on the wave to that same point on the next wave.
Amplitude (A) - One-half the wave height measured from equilibrium line to crest or trough.
Period (T)- The time it takes to complete one cycle or for one complete wave to pass a particular point.
Frequency (f) - The number of waves that
pass a particular point in a given time period. Units are Hz.
Speed (v) - frequency times wavelength.
Energy (E)- Expressed in Joules (J) The amount of energy transferred to an object when a force of one newton acts on that object in the direction of its motion through a distance of one meter
Day 2
Team meeting and planning.
Use the engineering design process to build and test devices.
Document design changes in your engineering and design presentation.
Complete the Resonance Calculations lab in Google Classroom
Day 3
Project development.
Day 4
Project development.
Day 5
Turn in project and Resonance Calculations from earlier in the week.