Why does water feel hard when you jump into it?

Water can feel incredibly hard if you fall onto it horizontally, extending your arms and legs. It can feel almost as solid as concrete. Why does this happen?

Falling into water is not as harmless as it might seem, whether it's a jump into a public pool, professional diving, or falling from an airplane. Reports indicate that professional divers sustain injuries from hitting the water.

Darren Taylor, also known as "Professor Splash," a professional show diver, is listed in the Guinness World Records. For the reality show "Go Big," he belly-flopped into a kiddie pool from a height of over eight meters into just 25 centimeters of water.

Even at a greater water depth, a belly flop from such a height would be very dangerous for an amateur. It is reported that even Professor Splash has suffered concussions and injuries throughout his tumultuous career.

There are many factors that can influence whether you will get injured when falling into water. Height is one of the key factors.

When you enter a pool, the water feels pleasant. However, when you fall into the pool, the water feels much harder.

When you fall onto solid ground, you feel a counteracting force. This can break your bones. But water is more malleable. It parts before you as you dive in.

As you enter the water, a resistance force acts on your body. This force depends on your speed and the area of contact. When you enter the water, your speed is low, and the water resistance is also minimal.

When you jump into the water, the speed increases with the height of the jump. Consequently, the force of water resistance increases with speed.

With the correct entry, the contact area is smaller, and the body's speed is gradually reduced. When falling on your stomach, the contact area is larger, and the body's speed is reduced abruptly. In this case, the water resistance force can be significant.

When falling from a great height, such as from an airplane into the water, the likelihood of fatal outcomes is very high, regardless of the contact area: the speed is simply too great.

To make the dive into the water painless, you must minimize the contact area. You should enter the water vertically, with your legs or arms first. But not your stomach.