The imprints of raindrops preserved in 2.7bn-year-old rock are being used to figure out what the atmosphere was like on the early Earth. Scientists have used the depressions drops left to calculate how fast they were going as they impacted the ground. This has allowed them to determine the density of air in ancient times. Read more
Why raindrops come in many sizes We might never consider the size of the raindrops as we hurry for cover, but their variety has puzzled scientists for many years. Now, by filming one falling raindrop, researchers in France have explained why the drops are an array of so many different sizes. Reporting in the journal Nature Physics, the team described how the drop deformed and burst as it fell. Its fragments matched the size and distribution of drops in natural rain.
Mathematics research could point to new understanding of liquid motion. Droplets of liquid have been shown to travel uphill when the surface is vigorously shaken. In a similar process to raindrops on car windscreens, small ones stay in place while bigger ones roll down the window. This is due to the surface tension holding the small drops onto the screen until they get to a size where the force of gravity is greater than the surface tension. University of Bristol mathematicians have demonstrated that the small drops can defy gravity and even travel uphill - even at an incline of 85 degrees - if the surface strongly vibrates up and down.