A fusible alloy is a special type of metal that can melt easily when it gets hot. It's like when you have ice in your hand and it melts because it gets warm.
Now, this metal can melt at a lower temperature than other metals like steel or aluminum. This means that even if you heat it up just a little bit, it will start to melt. It's kind of like when you put a popsicle in your hand on a warm day and it starts to melt a little bit.
Fusible alloy is used in many different things like fire sprinkler systems that trigger the water to sprinkle when they get really hot. It's also used in some electrical fuses that help protect things from getting too hot and causing a fire.
Overall, fusible alloy is a very special metal that can save lives and prevent fires by melting easily when things get too hot.