Why Do Standing Waves Form with Two Free Ends?

[huyhohoang]

Hi everyone!
As we all know standing wave of 2 fixed ends formed by the combination of coming wave and reflection wave. But I wonder why there still have a reflection wave combinating with coming wave to form standing wave of 2 free ends?
Many thanks.

 

[drvrm]

As we all know standing wave of 2 fixed ends formed by the combination of coming wave and reflection wave. But I wonder why there still have a reflection wave combinating with coming wave to form standing wave of 2 free ends?
Many thanks.

the standing waves are formed in open end organ pipes -open at both ends -in whistling through an open pipe one must have felt a difference in intensity of the sound produced.
when sound waves(composed of region of compression) travel and reach the open end
it must be pushing in the air outside like a sudden 'push of energy/and displacement of the air molecules'
and for a very short time interval a 'low pressure region may have formed at the open end and
neighboring air will push to fill up this void-
and in this process a compression can be formed at the end which can travel back as reflected wave and can give rise to standing wave..

 

[huyhohoang]

Thanks for your answer.