How to Make a Paper Popper - Loud Snap From One Sheet of Paper

Lay a sheet of letter or A4 printer paper on the table in landscape, long edges running left to right. Take the top edge, bring it down to the bottom edge and line the corners up as best you can. Close is good enough here.

Run a finger along the fold once to set a light crease, then open the sheet back up. That faint line across the middle is your guide for the next two folds. Do not press hard. A sharp crease is where the paper rips later.

Take the top edge of the open sheet and fold it straight down so it lands right on the center line. Keep the fold parallel to the crease, with the two top corners sitting on it. The fold does not have to be exact to the millimeter.

Press along the new fold with your fingertips to hold it. You now have a flap covering the top half of the sheet.

Take that same folded edge and fold it down again on top of itself, so the top of the paper meets the center crease a second time. The flap gets half as tall and twice as thick.

Press it flat with your fingers. This doubled strip along the top is the bar. It is the part that holds the air pockets closed until you throw the popper, so keep it neat and keep it flat.

Now the whole bar moves. Take it across its full width and fold it over onto the flat part of the sheet, using the line where the bar meets the sheet as the hinge. Roll it down rather than flipping it, and line up the long edges.

Push the bar flat with both hands. It is a good deal stiffer now, which is what you want.

Fold the bar over one more time in the same direction. It resists now, so roll it over with your fingers instead of trying to crack a sharp crease into it.

Lay the strip on the table and run both palms along the whole length of the bar to flatten it. You should be holding a long strip with a chunky, stiff bar down one long edge and a single layer of paper on the other. That single layer becomes the flap that pops.

Turn the strip over so the bar is underneath, then fold it in half left to right, short edge to short edge. The bar makes it too rigid to fold flat, so push a thumb into the back of the strip at the middle and let it bow into a curve first.

Bring the two short edges together, line them up, hold them, and pinch the curve down into a crease at the middle. That is the popper. It looks like a flat wedge with the bar along the outer edge and open ends on the other side.

Hold the popper so the open ends point toward you and the bar sits on the left. Grip the bar with one hand. With the other hand grab the loose outer corner on the right side.

Pull up on the bar and push down on the corner at the same time. The inner layer of paper slides out from between the outer layers and hangs below them. Stop as soon as you see it move. That sliding layer is the flap that makes the noise.

With the inner layer slid down, look at the two corners at the top of the popper: one on the bar side, one on the loose side. Pull the slid layer down a touch further, then bring those two corners together and pinch them between your thumb and first finger.

The inner layer curls into a loop between them. That loop and the fold behind it are the two air pockets. Keep the pinch tight and keep every other finger off the paper.

Look at the sliding edge, the free flap that will pop out. Set it level with the two pinched corners, or a little above them. Lower is louder but harder to set off, and too low will not go at all.

Hold the corners tight, then throw the popper down hard, the same motion as pitching a ball, without letting go. The air catches in the pockets and the flap snaps out with a crack. To reload, fold the flap down once, fold it back once, then slide and pinch it again.