Past Project

Speech Droplets

Droplet generation and disease transmission

High-contrast imaging of fine droplet trajectories expelled during a cough.

High-speed, laser-sheet imaging of droplets expelled during a cough.

When a sick person coughs or sneezes, they produce tiny droplets that can spread over large areas, potentially carrying germs to the people around them. There is also growing recognition that even ordinary speaking can generate fast-moving droplets.

Here, we use a bright laser to illuminate the droplets generated during talking. We study two scenarios: (1) a person saying the tongue twister “Peter Piper picked a peck of pickled peppers” , and (2) a person vocalizing the sound /pa/, as in the second syllable of “papa”.

Tongue twister

Droplet trajectories while saying “Peter Piper picked a peck of pickled peppers.”

The /pa/ sound

Droplet trajectories while vocalizing the /pa/ sound.