SPOKANE, Wash. (NBC News) – As some states begin to issue mask mandates, many people wonder how effective masks really are.

Dr. Rich Davis is the microbiology director at Sacred Heart Medical Center in Spokane, Washington.

He has tested four situations with masks and without masks – talking, singing, coughing and sneezing.

“It’s a demonstration of where respiratory droplets go and how easy they are to transmit and how a mask is effective at blocking those. That’s really the key take away,” he said.

In this experiment, he placed a petri dish in front of a reporter, with the petri dish at about the distance of where another person’s face might be. The reporter than talked toward the dish. The experiment was repeated with the reporter wearing a mask.

The reporter also sang to 2 petri dishes, coughed at 2 petri dishes and sneezed at 2 petri dishes. In each case, the dishes were marked to know which ones involved the reporter wearing a mask, and which ones involved no mask.

Dr. Davis put the dishes in an incubator and waited 24 hours for the results.

In all four cases of wearing a mask, there is little to be seen in the petri dishes. In the cases where the reporter did not wear a mask, there are yellow dots in the dishes, especially in the ones where he coughed and sneezed.

“I think we’re coming into a new reality where masks fit into that very social-conscious paradigm,” said Dr. Davis. “You do simple things that everyone can do. It’s not going to be 100% effective, but if we all do it, it’s going to definitely make a difference in preventing things from spreading from one person to another.”