TERRY SATER REPORTS. >> DAY FIVE, SURGICAL MASK, TRIAL ONE. TERRY: DUKE UNIVERSITY RESEARCHERS TESTED A VARIETY OF MASKS, USING A LASER TO SHOW THE DISEASE PARTICLES SPREAD BY PEOPLE, EVEN DURING NORMAL CONVERSATION. >> BY COUNTING THE LIGHT FLASHES , YOU GET AN IDEA OF HOW MANY DROPLETS YOU EMIT. TERRY: WE WANT TO DEMO — TO KNOW WHICH MASKS YOU SHOULDN’T BUY. DR.