By C1 Staff
A question recently posted on Quora asked why jail bars are stereotypically depicted as horizontal in cinemas. Check out the responses below for the answer, and add your own thoughts in the comments.
Namit Kothari
Very interesting question. I believe the answer lies in Newton’s third law of motion. The bars are made thick to prevent a prisoner to break out free.
Case 1: Assume the bars are horizontal. In this case, the prisoner has a better chance to bend the bars as the ground gives the desired ‘normal reaction’ to the prisoner against the force applied by the prisoner to bend the bars. This makes it easy to achieve the result.
Case 2: Assume the bars are vertical. The force required by the arms (way weaker than thighs) is same but the arms require better leverage than thighs to bend the bars which makes it way more difficult to break free.
Could this have been inspired from the bird cages?
Yes, highly probable. The cages in the zoos/bird cages could have been a very potential inspiration for the vertical construction of bars.
Also, I wish to reproduce a very interesting comment:
Do you really think all that was considered in the first design? After all the vertical appearance of jail bars is quite old.
Honestly, I am not sure. I think it has to have an evolution history over time and fail cases. The ones I have cited might not be the primary reason but could have been a definite consideration. Cost factor and security does become a primary factor in a large scale implementation (I mean for the current time). As far as I know most jails are very old, esp in India, where cost would have been a secondary factor at the time of building the prison
Parijat Roy
1) It requires less steel!
Consider this grid below. It has similar height and width proportion of a prison door.
Now if I put bars vertically, I’ll need only 2X5=10 units of rod. But maintaining the same gap if I put bars horizontally, it’ll take 3X4=12 units. This is true for all tall rectangles. Vertical configurations require less steel. Less steel equals less cost.
2) If the bars were horizontal, the prisoners would climb up the bars and hop on them until they buckle and comes off their socket. It’s a lot easier to use one’s weight to apply a force than to apply it with one’s arms as in the case for vertical bars.
