Look at the picture on the main screen.

To make this 'candle blower', you need a short length of cardboard tube, two pieces of plastic sheet (for example from a plastic bag) and two sturdy plastic bands, as well as a candle.

Stretch the plastic sheets over the ends of the tube and fix them with the bands. They must be stretched tightly, like drums.

Make a small pinhole in one and place this end close to a candle. Tap the plastic on the other end of the drum very sharply. It will send shock waves of air (vibrations) down the tube and they will all come out of the tiny hole, making the candle flicker just as if you had blown on it.