Saying his name gives us '90s flashbacks but Bill Nye is all over the internet right now with a very 2020 message: Masks are important.

The 64-year-old "science guy" took to TikTok to demonstrate how face masks work to reduce the spread of COVID-19. The video is especially great for showing kids how masks work and why we wear them.

In the clip, Nye tries to blow out a candle while wearing different types of masks and scarves showing how effective each one is at blocking the movement of air.

"Face masks like this one prevent particles from getting into the air and then into your respiratory system," Nye explains while holding up a surgical mask. He also holds up a homemade fabric mask (made out of two layers of cloth and a pipe cleaner to help it fit the bridge of the nose).

"It blocks the movement of air very effectively," he explains, showing how he is unable to blow out the candle directly in front of him when he's wearing it. "If you're wearing one of these, you're protecting yourself and those around you."

Bill Nye on TikTok

"The reason we want you to wear a mask is to protect you, sure. But the main reason why we want you to wear a mask is to protect me, from you, and the particles from your respiratory system, from getting into my respiratory system," says Nye. "Everybody, this is literally a matter of life or death, and when I say literally, I mean literally! Literally, a matter of life or death! So when you're out in public, please, wear a mask!"

New York Gov. Andrew Cuomo posted Nye's video on his Twitter account, captioning it: "Listen to Bill Nye."