I would like to know how a gothic arch can stay up in place without falling. Thanks you very much. The thing that holds any kind of arch together is gravity.
Gravity is a force that pulls everything on the earth straight down.
But it can only push against the flat edge of the bricks next to it. So what actually ends up happening is that it pushes the brick on its left a little bit to the left and a little bit down, and it pushes the brick on its right a little bit to the right and a little bit down. The force on each brick to the side is then transfered much the same way to each of the rest of the bricks the rest of the way down. If this doesn't exactly make sense, you can think of it in terms of some of the basic laws of physics. Also, this means that the force that the top brick applies to the brick on its left is equal to the force that it applies to the brick on its right.