When you close a window, it helps reduce the transmission of outside sounds into the room, but it doesn't completely eliminate them. The extent to which sound is blocked depends on the design and quality of the window, as well as the type and intensity of the sounds outside.
Windows typically consist of glass panes and a frame, which can provide some level of insulation against sound. When you close a window, it creates a physical barrier that obstructs the direct path for sound waves to enter the room. This barrier helps reduce the volume of sound that can pass through.
However, sound can still find alternative paths to enter the room even when the window is closed. For example, sound can transmit through vibrations in the building structure, gaps around the window or in the frame, or through other openings like doors or ventilation systems. If there are significant gaps or poor insulation, the window may not be very effective in blocking outside sounds.
To enhance sound insulation, you can consider using soundproofing techniques such as adding weatherstripping or sealants around the window frame, using double or triple-pane windows with insulating gas in between, or using sound-absorbing curtains or blinds. These measures can further reduce the transmission of outside sounds and improve the overall soundproofing of the room.