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Slide 2 Visible sounds Created by: Gyula Nyerges Slide 3 Instruments Slide 4 Instruments Try to guess what kind of musical instrument you are hearing! Time-avarage holographic interferograms Slide 5 Standing waves Linear (bowed string) Take a look at the movements of the string lighted by a strobe light! Two-dimensional systems (square plate) Slide 6 Kind of material is important Bells made of different materials CCCCopper BBBBrass LLLLeaden Try them! Sonic speed varies with the medium the sound travels through. Slide 7 Human voices What is the difference between vowels? aaaa eeee iiii oooo UUUU Use the microphone, and pay attention to the various spectras! Slide 8 Handmade instruments There are a lot of things around the house that can be used as a musical instrument. Cover Cover Bottle Bottle Spoons Spoons Straw Straw Slide 9 Measuring of the sonic speed Make a horn out of a drinking-straw! Measure its length, and the frequency of the produced sound! You can calculate the sonic speed using these data. Example: Slide 10 Doppler- effect Revolving pipe Spin around the whistle above your head, and at the same time blow into the tube. The audience hears sounds with different frequencies. Slide 11 Retardation, acceleration Normal tempo Normal tempo Slow down Slow down Rev Rev Back Back Slide 12 Animal-sounds Bat ( quarter speed) Bat ( quarter speed) Dolphin ( quarter speed) Dolphin ( quarter speed) Slide 13 Variable stars Available data: Available data: Brightness Color index surface temperature Doppler shift of absorption lines radial velocity pulsation diameter Slide 14 Variable stars Slide 15 Changes in the state of a variable star as a function of time Slide 16 Model of stars working The change in pressure within the interior of the star is actually a very deep sound. Slide 17 Star-horn Star-horn Overtones in the case of a whistle based on organ-pipes and a stellar model Slide 18 Variable stars Surface waves Surface waves Stars don't just pulsate radially, which further complicates the model. Slide 19 Slide 20 Sources Utunk a csillagokba (Way to stars) CD-ROM Animations by Zoltn Kollth Utunk a csillagokba (Way to stars) CD-ROM Animations by Zoltn Kollth www.partnersinrhyme.com/soundfx/batsounds.shtml www.partnersinrhyme.com/soundfx/batsounds.shtml home.snafu.de/ulisses/analysis/spec1.htm home.snafu.de/ulisses/analysis/spec1.htm www.tar.hu/fizfoto www.tar.hu/fizfoto metal.elte.hu/~phexp/st_kgy.htm metal.elte.hu/~phexp/st_kgy.htm Slide 21 THE END Restart