Robinson recovered from his illness with a newfound sense of the importance of Christianity. Thinking that he was stuck on the island for good, he explored around the island more, discovering a forested area with various fruit trees, where he built a smaller dwelling in addition to his main one.
It is because when it is placed in a freezer, the cold slows down the chemical reaction that makes it glow. Basically, you freeze the chemicals inside the glow stick.
