system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How do masks work if germs are smaller than the fabric?
gpt
Many germs and viruses can only travel through the air on water droplets. The fabric of your mask catches those water droplets as you breath/sneeze/cough, preventing them from spreading as far as they would without a mask. 

You can easily test this yourself if it's cold where you are just by going outside and breathing normally with and without a mask.  Without a mask, you'll see your breath travel quite a few feet. With a mask, you'll barely see your breath at all.