Why is a thermometer jerked before taking temperature of a person?

What is the thermometer used to measure the temperature of a furnace?

Which among the following thermometers is preferred for measuring temperature around 125^@c

The thermometer suitable for measuring a temperature of about 2000^(@)C is

Why does an athelete run before taking a high jump ?

Explain why a clinical thermometer is exclusively used to measure the human body temperature and a laboratory thermometer is used to measure the temperatures of different substances but not to measure the human body temperature .