If Peter Powers was an only child, it's possible he may never have become a hypnotist.

That's because he learnt his craft by trying to make his younger brother do silly things.

It started when he was 12 and watched a movie on TV that featured a hypnotist waving a pocket watch in front of a subject.

"When the movie finished I said 'let's get my dad's pocket watch out', because it was done with the cliched pocket watch," Powers says.

"He tried it on me and I tried it on him and I'm saying, 'look at the watch, your eyelids are getting heavier'. I was just copying what I'd seen in the movie.

"He closed his eyes and I thought he was pretending. But there was something about his face that made me think 'something's happened here'."

So the next day he went to the library and borrowed a book by hypnotist Melvin Powers (Peter Powers' stage name is a tribute to Melvin) and then continued to experiment on his brother.

He would also hypnotise people at school, which is where he got a taste for doing it in front of an audience. A teacher at the time noted that it would likely mean Powers would turn this into a career - and he was right.

But despite the years of putting people under and making them do funny things, Powers still isn't sure how hypnosis really works.

"I can better describe how to achieve it than how it works because no one's really sure how it works. What you're doing is you're suppressing the critical faculty, which is part of the conscious mind.

"An example I could give to illustrate it is when you're asleep, your critical faculty's dormant as well.

"That's why when you dream you can fly or all kinds of other weird things - it doesn't seem out of the ordinary to you at the time. You accept anything and everything in a dream."

So by getting people to focus intently on an object - like, say, a pocket watch - Powers says you can suppress that critical faculty and start putting suggestions into people's subconscious.

But it won't work on everyone. Some people are just naturally resistant to it. Also, during Powers' show some volunteers may not go under and they're sent back to their seats.

Powers says that's because a relaxed person would need a different form of hypnosis than someone who is a nervy or uptight person. But because Powers only has 10 minutes to get everyone under before the show starts, he can only choose one of the methods.

So some volunteers have to watch instead of take part. And Powers stresses that it's only ever volunteers who appear in his shows.

"I don't pick people out," he says.

"A lot of people get nervous, or don't even come to the show because they're frightened of being one of those people pulled up on stage.

"But I only ask for volunteers. I never choose people out of the audience, so if nobody volunteered there wouldn't be a show - but thankfully people always do."