RESONANCE IN AIR COLUMNS
STANDING WAVES IN A STRETCHED STRING OF LENGTH OF L FIXED AT BOTH ENDS:
SCIENTIFIC NAME  MUSICAL NAME  
First harmonic  Fundamental  L = λ/2  
Second harmonic  First overtone 
L = λ


Third harmonic  Second overtone  L = 3λ/2  
Fourth harmonic  Third overtone  L = 2λ 
CLOSED END OF AIR COLUMN Acts as a fixed end
First resonant length Fundamental mode 
L = λ/4 f_{0} 

Second resonant length First overtone 
L = 3λ/4 3f_{0} 

Third resonant length Second overtone

L = 5λ/4 5f_{0} 
OPEN END OF AIR COLUMN Acts as a free end
First resonant length Fundamental mode

L = λ/2 f_{0} 

Second resonant length First overtone

L = λ 2f_{0} 

Third resonant length Second overtone

L = 3λ/2 3f_{0} 

Fourth resonant length Third overtone

4th Harmonic  L = 2λ 4f_{0} 