clhs sciblog

A team from Japan has been doing experiments to see what happens when water droplets of different sizes fall from heights of 10 mm to 488 mm onto a target made of silicon carbide with grain sizes ranging from 4 microns to 50 microns.  They then use lasers radius and depth of the crater made by the water droplets.  Each water droplets was about 4.8 mm in diameter and they made cylinder shaped craters.  It was also found that low-speed impact on small grains didn’t compress the grains on the surface at first, but then they created craters that were 1.5 mm deep as the drops compressed on the grains.  Larger grain size resulted in shallower craters.  They got a different result when they tested high-speed impacts.  When they used high-speed impacts the drop compressed the grain immediately.  This high-speed impact caused a convex “bump” higher than the original surface of the grain.  The grains are brought together with the initial impact and as the drop spreads out they are dropped in the middle when the drop sinks.  Katsuragi discovered that the crater’s radius is proportional to the ratio of grain density to water density at to a constant called the Weber number.  Read more.

This research is something that can be very influential to the research and exploration of different planets.  This will help scientists discover if there are any signs of water on different planets, and also in fossils.  Fossilized depressions of craters left by raindrops have been found.  This study would help scientists figure out if these depressions were caused by raindrops.

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