What is a simple barometer?

A barometer for forecasting sunny days. Sometimes it also refers to a sign before something happens.

When I was in school, the psychological committee in the class sometimes gave this to the teacher to tell the good and bad things in the class, and the barometer was similar to this report.

Barometer also refers to the central number of a unit, which affects the whole.

In engineering construction, the barometer records the weather every day, which can check and record the construction content of the day in detail and find out the cause of the construction accident.

A barometer is also called a barometer. See the barometer for details.