Step 1: The Sensor
Thus this sensor is ideal for measurement where the result is to be interpreted by a human. A multimeter in it volts range will show the temperature with an offset of fifty. Zero degrees Celsius will result in 500 mV. 100 degrees Celsius will result in 1.5 volts.
Since I was making this to investigate the temperatures in and around a refrigerator, in order to troubleshoot the making of ice cream, I decided to encapsulate the sensor in plastic, it being easier to manage than metal.
The downside is that it might not resist heat very well, as the plastic tube becomes soft if immersed in boiling water. The plastic does not conduct heat very well and so the sensor takes some time to respond to the applied temperature.
If the above points are important to you, there is another instructable on the same subject: http://www.instructables.com/id/Waterproof-a-LM35-Temperature-Sensor/