02 Mar, 2013
In a tin
PRESENTATION: Any mechanical system with some elasticity can oscillate when externally disturbed. A greater or smaller amplitude of oscillation depends on the relationship between the characteristics of the damped system and the frequency of the external force.
- Ten Things You Should Do with a Tuning Fork, James Lincoln, Phys. Teach. 51, 176 (2013)
- Demonstration of simple and dramatic resonance in a whiskey bottle, Norihiro Sugimoto (Stray Cats), Phys. Teach. 51, 58 (2013)
- A Simple Experiment to Explore Standing Waves in a Flexible Corrugated Sound Tube, Maria Eva Amorim, Teresa Delmira Sousa, P. Simeão Carvalho, andAdriano Sampaioe Sousa, Phys. Teach. 49, 360 (2011)
INTRODUCTION: Resonance is a phenomenon that is produced when a body that is capable of vibrating is subjected to the action of a periodical external force whose period of vibration coincides with the characteristic period of vibration of the body itself. This means that a relatively small yet constant force can make the amplitude of an oscillating system become very large.
In such circumstances, the body vibrates, progressively increasing the amplitude of motion. This effect can be destructive in some rigid materials such as when a glass shatters as a soprano sings a note that reaches and sustains its frequency of resonance.
OBJECTIVE: To demonstrate the effect of resonance on a tin.
MATERIALS: tin, scissors.
SETUP: Use the scissors to cut 7 vertical strips in the can, each about 1 cm wide, separated from each other so that they can vibrate, and each with a length that varies continually from one strip to the next in such a way that the shortest strip is 1/3 long and the longest 2/3.
On the other side of the can, opposite the middle strip of the 7, cut another strip with the same length as this middle one.
EXPLANATION: If we make the single strip cut into the opposite side of the can vibrate, resonance will be produced in the middle strip opposite it that has the same length, and also, to a lesser extent, in the strips closest to it. This is due to the fact that they vibrate with similar frequencies. If we cut the single strip shorter, then the shorter strips will now be seen to resonate.
CONCEPTS: resonance, resonance frequency, natural frequency, resonance oscillator, acoustic resonance, mechanical resonance.
- Tipler P.A. Física. Barcelona: Reverté, 2010.
- De Juana J.M., Física General, Pearson, 2009.
- Serway R.A y J.W.Jewett. Física, Thomson-Paraninfo, 2010.
- R. Ehrlich, Turning the World Inside Out and 174 Other Simple Physics Demonstrations, Princeton University Press, 1997.
STUDENTS 2011-2012: Cristian Rueda, Álvaro Santiago, Carlos Saso
LINK pdf STUDENTS (in Spanish):