Marc Clayton, a mechanical engineer in APL's Aeronautical Science and Technology Department, has at least one thing in common with Jeopardy's Alex Trebek: Come show time, they both prefer that people respond with a question. Since 1992, Clayton has brought to various Maryland elementary schools an APL-sponsored show that is one part education, two parts fun. In his one-man routine dubbed "Marc's Groovy Science," the much-in-demand Clayton demonstrates fundamental scientific phenomena using mostly ordinary household objects. His intent is to engage the imagination of his audience and bring a thrill to learning. A fan of inquisitive minds, Clayton likes nothing better than when hands shoot up after one of his experiments. His first performance was at APL's 50th anniversary celebration, held at the Lab's Kossiakoff Center. APL was looking for acts to entertain at the family-oriented event, and Clayton thought it a perfect opportunity to combine his passions for performance and science. The show was a hit, and from that point on, he was hooked. In his APL guise, Clayton for the past 17 years has been dealing with the operation and maintenance of the wind tunnel at the Avery Advanced Technology Development Laboratory. An enthusiastic, hands-on sort, Clayton talks about the pumps and compressors he contends with the way a young boy would talk about baseball cards and video games. The Gazette recently sat down with the animated Clayton to discuss his groovy show. The interview, not surprisingly, turned into a quick science lesson that was as enjoyable as it was informative.

Q. How did this performance side of you get started?
A. I would have these shows at the house. I would invite around 75 people, and 10 to 15 of us would put on an act. I would emcee all the acts. People would show up, and they would sing or dance, juggle or tell jokes. It was such a ball, and I had such a great time putting on my little bits. I put so much energy into it.

Q. How long was that first show, at APL's 50th anniversary event, and what did you do?
A. I did "The Sensational Science of Sound." That kicked it off. It was a 45-minute show, and I did three shows.

Q. What kind of shows were you giving in those early days?
A. I started off with sound effects. I'd say, Do you think going to the dentist would be a bit more pleasant if the drill didn't sound like [makes drill noise]? Then I would show a picture, like a lion doing a roar, but with no sound; then I put in the roar, and go, Hey, sound kind of completes the picture, huh? Now that we have a sense for why sound is kind of important, let's look at it. I had a toy with a little speaker inside, and it would emit a sound. You could throw it around the audience and hear the Doppler effect. It is always very fundamental things with me.

Q. How do you begin each show?
A. It varies to keep it not boring for me. Typically, if it's a large crowd and I have my sound system, the big catch is I alter my voice. I'll have a high-pitched voice or a deep, resonating, monster voice. Or echoes. Or I'll sound like a demon. When an adult in front of elementary school kids has a voice the sound of a fly, they just love it.

Q. No poof of smoke?
A. No. I'll say, Let's do something. You watch it, and when we are done, tell me if you made a really interesting observation, or if you have a question about what you saw. Because to me science always starts with observation and questions. I do things where the outcome isn't what they expect.

Q. You use balloons, right?
A. You take a balloon, put it in a beaker and let the blown balloon stand there. Then I take liquid nitrogen and pour it over the balloon. The balloon will collapse, keep collapsing, keep collapsing, until I stop pouring. Then I take the balloon, put it in my hand, and it's a crinkled up, crumpled mass. Then you hear it crinkle and it starts to grow, starts to expand, expand, expand, all the way back to its normal state. Any questions?

Q. What just happened?
A. It is a great exaggeration of a fundamental principle: Cold molecules slow down; hot molecules get energy and go faster. People think, Well, where did the air go and how did it get back into the balloon? What makes you think that the air went anywhere?

Q. These are never just tricks?
A. It's not magic. It's science. The only difference between magic and science is, magic creates mystery by hiding the truth--that is where the excitement is. Science, on the other hand, actually finds discovering the truth exciting. Every magic trick you see is nothing but incredibly fundamental science with a few of the pieces hidden to make it appear that it is something that it is not.

Q. What is a can't-miss experiment during your show?
A. I would have to say the favorite one that I always save pretty much for the end is the boomer, an explosion. You got to have your obligatory explosion.

Q. A boomer?
A. Classically, a potato gun. With the boomer, I use a sponge. I talk about why I use a sponge vs. a potato, and why I use propane instead of wet fuel. And then I shoot a sponge across the assembly hall, and it lets out a really nice bang. I mean NICE. So, I say, What is interesting about that? Does anybody have any questions? Then we talk about needing fuel, air and heat to get it going.

Q. Do you have a stage name?
A. Groovy Mark.

Q. Do you dress the part of a scientist?
A. I don't wear anything special because I've watched people who do and it always in my eyes made it look like a scientist is something different than they are. When I go on stage I'm typically in jeans, usually black jeans and a groovy T-shirt.

Q. So, no overcoat with the pens in the pocket?
A. No, because [the students] don't like that. When they see someone who looks kinda normal--and you know I'm not your normal-looking engineer--they're hopefully seeing something that they wouldn't mind growing up to be. A lot of young girls and guys, they are not interested in overcoats and bow ties and pocket protectors. That is not the image it should be. It should be somebody with enthusiasm and fun and happy and likes what they do. You know, just casual.

Q. How many shows do you do?
A. I average one a week. Some schools I've been back to every year since I've started. But when I see the students again, I expect a little more out of them, and I tell them, Don't tell the others what is going to happen.

Q. You are, in effect, representing APL when you do your shows, correct?
A. Yes. But I started off doing these on my own, on my free time. I would go to school on career days. Then I started letting people know that I have an interest in doing these sorts of things.

Q. And the Lab still sponsors you?
A. Yes. I get to borrow the Lab's van, and APL gives me the liquid nitrogen, something you're not going to get many places easily.

Q. Do your show experiments ever not go the way you planned them to?
A. Sure, balloons pop, things drop, the boomer misfires, and kids say the darndest things.

Q. How do the children typically respond to your show?
A. That is what has kept this going, because the response is so incredible. Administrators and teachers routinely come up to me and ask if I'm a teacher. I'm just having a good time with science, doing some crazy stuff, and they are engaged.

Q. How do you want children to respond?
A. Watch. Listen. Make an observation. Ask a question. That's that.

Q. You sound like you have a lot of fun with these shows.
A. I enjoy being with kids, much more than adults. Kids under the age of 13 especially are much more at ease about being free and cheerful, lighthearted and inquisitive. I just enjoy being with them. I didn't enjoy being a kid as much, because there were bullies. But now, they don't scare me anymore.

Q. What aspect of nature or science just amazes you?
A. The way the ocean of air we live in works. The way it pours from room to room. The way the hotter air floats to the top, and the colder air floats to the bottom. When I see a bird flying, or a kite flying or the trees bending, I'm like, Wow. It just blows me away.

This is the third in an occasional series of informal conversations with staff and faculty who do unique work or have unusual outside interests. If you know someone you think others in the Hopkins community would like to read about, please write to Lois Perschetz, Gazette editor, at lwp@jhu.edu.