@MrMoody - No, I think the Tesla coil is a different kind of electricity.
Science fairs typically have what’s called a Van der Graaf Generator. It’s basically a silver ball and a rotating crank. When you spin the crank it generates static electricity inside the ball.
Then you take a small probe and extend it near the big ball, and you can start seeing the static sparks fly and hearing the clicks of static electricity.
It’s a simple concept. You can get the same effect by rubbing your hands back and forth across the carpet, although that will give you the shock but not the sparks most of the time.