Genesis 6: 16: A window shalt thou make to the ark, and in a cubit shalt thou finish it above; and the door of the ark shalt thou set in the side thereof; with lower, second, and third stories shalt thou make it.
The word “window” of Genesis 6: 16 is the Hebrew word “tsohar”, which means, “light of the noon day sun”.
This window that God required for the Ark was to be the source of illumination whilst the world was enveloped by darkness during the Great Flood.
Genesis 8: 6: And it came to pass at the end of forty days, that Noah opened the window of the ark which he had made:
The word “window” of Genesis 8: 6 is the Hebrew word “challown”, which means, “piercing of a wall”. The Ark was fitted with “challown” (windows) to provide natural light, but this “challown” was of no effect during the great deluge.
The “tsohar” of Genesis 6: 16 was not a window as we know it. The “tsohar” was some device that absorbed energy to create an artificial light for illumination inside the Ark during the darkness of the Great Flood.
Noah lived in a civilization that was very advanced, and so certain technology was employed inside the Ark to provide the illumination needed during a time of global darkness.