The Covid-19 coronavirus is highly contagious. While we are urged to practice social distancing and wash our hands thoroughly and frequently, it’s still difficult to imagine how fast and wide the virus can spread in a short period of time. To help visualise it, Japan’s national broadcaster NHK conducted an experiment to show the rapid spread of micro-droplets, like those that carry coronavirus, in crowded places.
The ten-person experiment simulated a typical situation at a buffet restaurant. The only difference? One participant's palm was covered with special fluorescent paint prior to the experiment. Only visible under black light or in darkness, the paint represented the coronavirus droplets.
After 30 minutes of eating and talking without face masks on, dark light revealed the traces of fluorescent paint, which had made it onto the tableware, tongs, food and drink containers, and not to mention, all ten participants’ hands and three people’s faces. Although the experiment began with only one ‘infected’ person, by the end, all ten people could be considered ‘infected’.
A second run of the experiment, in which restaurant employees served the food onto plates, tongs were changed frequently, and diners washed their hands during and after the meal, showed very different results. The amount of paint remaining on people’s hands was reduced to a fraction of what it was in the first experiment and none of the participants had stains on their faces. So there you have it – although coronavirus droplets can spread fast in a crowded environment, it seems taking precautions like hand-washing can reduce the risk of infection.
In an earlier experiment, NHK and a group of researchers demonstrated how far and fast micro-droplets of the coronavirus can travel after sneezing, coughing and loud conversations, especially in poorly ventilated enclosed spaces.
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