Most of us [learn / academic] at school that warm air rises and cool air sinks. This has always [seemingly / appeared] to be a fundamental principle of science. However, a [studious / study] from the University of California, Davis found that there are circumstances [in / on] which cool air rises. Researchers discovered that in [tropics / tropical] atmospheres, cold air rises because of the lightness of water [wiper / vapour] . Apparently, in warmer and more humid climates, water particles become more [buoyant / floating] and can help cooler air rise. Lead researcher Dr Da Yang said: "Water vapour has a buoyancy [reflect / effect] which helps release the heat of the atmosphere to space and reduce the [degree / agree] of warming. Without this lightness of water vapour, the climate warming would be even [worst / worse] ."
The scientists said [humid / humidity] air is lighter than dry air at the same temperatures and pressure. This is called the vapour buoyancy [affect / effect] . It allows cooler air [contents / containing] water droplets to rise, which then forms clouds and [thunderstorms / thundery] . The resulting rain has a cooling effect in tropical areas. Another researcher, Seth Seidel, said more research is needed to find out the effects rising cool air [have / has] on climate change, and on its impact on [craving / curbing] the effects of global warming. Seth Seidel said: "Now that we understand how the lightness of water [regulates / waters] tropical climate, we plan to study [weather / whether] global climate models accurately [system / represent] this effect." The study is published in the [journal / journey] "Science Advances".