let's come to understand the scientific part behind this magical trick!!
When the ballon got nearer the nail in the first time , it poped easily and that's because of exerting all the pressure of the nail to one point. On the other hand, when the number of nails increases , the ballon takes much time to pop.
So we can observe that pressure is the ratio of the force to the area over which the area is applied. By
By increasing the surface area ,like what we did by increasing the number of nails in the bed, the pressure decreases so the ballon takes longer time to pop. while by decreasing number of nails, the surface area decreases and the pressure increases ,so the ballon pop easilly.
now, we can understand how the magician lies and walks on bed of nails without getting injured or losing any blood drop.