Are Double Pane Windows Soundproof?
Answer: If you use two panes of glass instead of one in the glass windows of the house, the sound outside the house is not heard by the person inside the house. Because, if there are two panes in the window, the air is trapped between the two panes. As a result, the outside sound will travel first from the air to the glass, then from the glass to the enclosed air, again from the enclosed air to the glass, and finally from the glass to the indoor air.
As we know, sound cannot propagate easily from one medium to another if the density difference between the two mediums is large. Therefore, noise from outside the room cannot enter the room air through different-density mediums. As a result, the person inside the room cannot hear the outside noise.