A child blows air at one end of a straw and . . .

Question : A child blows air at one end of a straw and slowly cuts pieces of the straw from the other end. What will be the outcome that will be observed?

Doubt by Mansi 

Solution : 

We know, 
In open organ pipe, 
𝜈_n=nv/2L

Clearly, 
𝜈∝1/L

So when the length of the straw is reduced then the frequency of the sound produced by the straw will increases.

Watch the below video for better understanding of the concept.