Fact 1: Water vapor condensing in clouds causes rain.

Fact 2: If it's raining AND barometer is steady, then predict rain.

Given the two facts above, answer the question "How can water vapor be detected?" with the following options: 
- Thermometer
 - radiography
 - A computer
 - satellites
 - Barometer
 - Evaporation
 - Windmills
 - Solar panels


 

     Barometer    