How long does it take for a brick to sink to the bottom of the ocean if you throw it into the Mariana Trench?
The Mariana Trench is the deepest trench on Earth, reaching a depth of 11,000 meters. You must know that the highest mountain in the world, Mount Everest, is only 8,848 meters above sea level.
Can a brick with a compressive strength of 30 MPa sink intact to the bottom of the Mariana Trench with a pressure of 110 MPa?
When a brick enters the water, its gravity is significantly greater than the buoyancy force, but it will soon experience upward resistance, which increases as the brick accelerates its sinking. After reaching a certain velocity, the sinking velocity of the brick will reach equilibrium, and this velocity is known as the terminal velocity. Calculations show that this velocity ranges from 1.28 m/s to 2.73 m/s.
As the depth increases, the water pressure also rises gradually. For every 10 meters of sinking, the brick increases its pressure by one atmosphere. When completely lowered to the bottom, it needs to withstand 1100 atmospheres. Although the pressure far exceeds the compressive strength of the brick, the brick will not be crushed.
The reason is that the uniform pressure of seawater makes the bricks stress on three sides at the same time, which enhances its overall compressive capacity. At the same time, the penetration of seawater keeps the pressure inside and outside the bricks balanced, avoiding the fate of being crushed.
The seemingly fragile bricks are actually tough enough to withstand enormous seafloor pressure, reaching a depth of 11,000 meters in about 1.12 to 2.39 hours.
