1. Problem no. 4 TEAM TALNET

2.  Discharging an electronic flash unit near a cymbal will produce a sound from the cymbal.  Explain the phenomenon and investigate the relevant parameters. A photo of cymbal

3.  Theoretical background  Determining main cause of emitted sound  Measuring of sound  Results  Conclusion

4.  Flash interacts with the material of the cymbal  Variants  By flashing the sound wave is generated  This sound interact with the cymbal and emits another sound wave  Pressure wave  Electromagnetic induction  Light

5.  A wave based on shift of grossness of air which is emitted when the flash is triggered could make the cymbal to emit sound.  We tried  clap hands  putting of transparent materials between flash and cymbal (glass, plastic materials)  flash on thermistor

6.  When the flash is triggered, a very high current goes through the gas-filled tube. Therefore could be generated changing magnetic field that might take effect on cymbal.  Experiments  flashing on razor placed on edge of table in near nonbalanced state  nonconductor between flash and cymbal  using flash on paper

7.  It could be that emited photons warm up air and this change the density of air in small area and therefore is changed level of pressure in this small area. And this is spreading like any other wave.  Sound:Triggered flash emits sound wave which is absorbed in cymbal and this makes cymbal to emit another sound wave, which may be in another frequency(ies)  Experimentation  putting of transparent materials between flash and cymbal (glass, plastic materials)

8.  All results of experiments are indicating, that the main cause of this phenomenon is light (photons).

9.  We have measured following characteristics of flash and cymbal  We observed:  difference between different places on cymbal  decreasing sound intensity with increasing distance flash from cymbal  dependence on cymbal´s colour  comparison energy of released flash and kinetic energy of falling paperclip

10. Distance We have measured intensity of sound emited by cymbal We have observed quick decrease of sound with increasing distance. Green line – distance 1 cm Blue line – distance 6 cm Red line – distance 17 cm

11. Clear cymbalBlackened cymbal

13.  We tried to find entries to figure out how much energy is released from gas-filled tube when flash is triggered.  We have found these approximated data:  Duration of flash  Power of flash  Factor fo conversion from electrical energy to optical energy  Flash is acting approximately in area of 1 sr

14. Paperclip We tried to determine the energy of photons, which are emitted by flash. We used following relations: Purple – fall of paperclip from 15 cm height Blue – fall of paperclip from 2 cm height Red – released flash from 1 cm distance E max – potential energy of paperclip in specific height (h) m – mass of paperclip g – gravity constant E f – aproximated energy of one flash a – aproximated coefficient k – number of photons h – Planck constant f – frequency of average photon c – speed of light λ – wavelength of average photon

15.  We have determinated, that the main cause of is light (photons)  We have observed basic relations between flash and emitted sound.

16. TEAM TALNET