The oven with double metal thermometer, baked good assistant

Remember once, my family and I at home baking homemade cookies, according to the steps to the oven temperature debugging to the right position, according to the time for baking, cookies had sprung up, finally we mystery, speculation about whether the temperature of the oven set do not tally with the actual temperature difference, cause temperature not good control, so the coke? In all waste of raw materials for a plate of cookies. So the next day, speak to colleagues, they said, why you don't have our own company production of oven using bimetallic thermometer? This watch is can be put into the oven to accurately display the oven temperature, so you won't because no error caused by the temperature. I have put our production of oven with double metal thermometer to forget, really should not. Later, I again homemade snacks at home, put the oven with double metal thermometer, put in my oven, only to find that set and actual temperature difference between the thermometer 15 & deg; C, blame not temperature control is not good, now I don't worry about the things in the sear, the oven with double metal thermometer, a baked good assistant.