Experiment with this doctor reveals why wearing a mask makes a difference

Although the argument about the efficacy of masks has already sprung up on social media, a demonstration by a US-based doctor demonstrating the effectiveness of wearing a mask has gone viral online, sparking the conversation once again.

“What does a mask do? Blocks respiratory droplets coming from your mouth and throat,” microbiologist Dr. Rich Davis from Spokane, Washington state tweeted while sharing pictures of bacteria culture plate he had coughed, sneezed and talked upon — one masked and the other unmasked.

"Two simple demos: First, with or without a mask, I sneezed, sang, spoke & coughed toward an agar crop plate. Colonies of bacteria indicate where droplets fall. An almost all of them blocks a mask," he wrote.