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agabwagawa OP t1_jbtuxr1 wrote

Reply to comment by superbob201 in When a wave travels goes from a higher impedance medium to a lower impedance medium, why would that cause a reflected wave? by agabwagawa

So when going from a high impedance medium to a low impedance medium, shouldn’t all that energy be transmitted into the particle motion? How can a reflected wave be generated?

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jellyfixh t1_jbtvu8y wrote

Waves are oscillatory motions. You can't have all the particles just leave and create a vacuum. So when the wave enters the lower impedance area there is low pressure in the high impedance area, and so particles must be drawn back in to balance it out forming a new reflected wave.

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agabwagawa OP t1_jc0x978 wrote

Got it! So the reflected wave at an interface going from high to low impedance just has a lower intensity than it would if it hit gone from low to high, but the reflected wave is the same frequency as the incident.

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hatsune_aru t1_jbuf38y wrote

the energy doesn't just disappear, the reflected wave also carries some energy.

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superbob201 t1_jbugnrs wrote

No, for the same reason that going from low to high doesn't transmit all that energy into the pressure. Neither pressure nor motion can have a sudden discontinuous change.

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michaelrohansmith t1_jbunr6l wrote

The high impedance medium can carry more energy than the low impedance medium. So when a wave goes from high impedance to low impedance some of the energy is reflected back because it can't go forwards.

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