Mobile wireless sensor networks are networks made up of lots of small devices called "sensors" that can transmit data back and forth to each other over a wireless network. These sensors can measure things like temperature, humidity, sound, and light, among many other things. The data from these sensors is then used to help make decisions about the surrounding environment, such as whether a room is too hot or too cold, or whether certain animals are present in the area. The sensors can also be used to monitor the health of people and equipment, like monitoring if a person has a fever or if a machine is running correctly.