It is a basic thermometer that wil repond to changing temperatures. The thermometer will measure the temperature (in Celsius) using the LEDs.
Two wires are connected to the breadboard and the GND and 5V on the arduino. The sensor is placed on the breadboard. Three wires are used (that correspond with the three legs on the sensor) to connect to the path of the GND, 5V and A0 on the arduino. Each LED (there are 5 of them) have their own resistor and are conencted to the pins (2, 3, 4, 5 and 6) on the arduino.