Final answer:
When unsafe to determine the boiling point or other physical properties of a substance, one should consult an expert and design a safe experiment that does not involve trial and error or exposing oneself to extreme temperatures. Instead, appropriate materials and methods should be chosen to measure temperature without risking safety.
Step-by-step explanation:
If it is not safe for you to determine a certain physical property of a substance, such as the boiling point of plastic Lego pieces, you should consult an expert rather than attempt potentially dangerous trial and error methods. Safety is paramount, and methods involving high temperatures could present significant risk not just to the Lego but also to personal safety and equipment. Instead of using a thermometer for unsafe experiments, it is wise to design a safe experiment that limits risks, such as avoiding extreme temperatures that could result in harmful emissions or physical transformations.
It is important to follow safety guidelines and laboratory rules to prevent accidents and exposure to hazardous substances. Selecting an appropriate material for temperature measurement, such as a liquid crystal thermometer or infrared pyrometer, depends on the experimental conditions and the physical properties of the material you're studying. Care should be taken to ensure that the temperature changes being measured do not cause undesirable phase changes in the materials being tested.