system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How do fuses stay lit underwater?
gpt
Water isn't an inherent counter to fire, it's not like it magically stops fire working. Water makes it difficult for ongoing fires to obtain oxygen, which they need to keep burning. Many explosives however contain chemicals called oxidants, which act as an alternate source of oxygen. Waterproof fuses use these, meaning the fuse doesn't need to get oxygen from the environment and thus water doesn't prevent it burning.