Good try but thats a thermostat
Robin, I believe there are thermometers that are accompanied by certifications/guarantees of accuracy but they are pricey, I don't know of any specific brands but I'll google it for ya.
ASTM thermometers are lab grade, but I believe most of them are mercury, and I am still looking for a digital one. I am very intereted in finding a more accurate device to measure temps as my two digital probes are 3 degrees apart almost 100% of the time.