Bats fly around using Ecolocation. This is when they send out noise signals and use the returning echo to determine the size of object in front and also the distance away.
We played a game of Marco Polo to illustrate this to the children. The children made beeping sounds and the child with the blindfold had to find them using their sense of sound only.
What does blind mean? It means you cannot see.
A very cool bat mask!