Final answer:
To properly measure the temperature of food with a bimetallic stemmed thermometer, you should wait 5 to 7 seconds before recording the temperature to ensure accuracy and food safety.
Step-by-step explanation:
When using a bimetallic stemmed thermometer to record the temperature of food, you should wait 5 to 7 seconds after inserting it before recording the temperature. This waiting period ensures that the thermometer has had enough time to accurately respond to the food's temperature. Bimetallic thermometers operate by the two metals, typically brass and steel, expanding and contracting at different rates, causing the stem to coil or uncoil, thus indicating the temperature on a scale.
It is crucial to measure the temperature precisely to ascertain food safety and to determine that it has reached a temperature high enough to kill any potential bacteria, as pointed out in Figure 4.7.7. The bimetallic thermometer should be inserted into the food, and you must pause for the recommended time to ensure reliability and accuracy of the temperature readings.
As per the procedures outlined in your science experiment, accurate measurement of temperature plays a pivotal role in observing changes in states of matter, such as melting of ice or boiling of water, and is essential for data collection and analysis.