Archimedes' principle: 


                                                          Archimedes' principle is a law of physics that states that an object submerged in a fluid experiences an upward buoyant force equal to the weight of the fluid displaced by the object. This principle explains why some objects float and others sink.

Key points of Archimedes' principle:

Buoyant force: When an object is submerged in a fluid, the fluid exerts an upward force on the object. This force is called the buoyant force.

Weight of displaced fluid: The buoyant force is equal to the weight of the fluid that the object displaces.

Floating and sinking: If the buoyant force is greater than the weight of the object, the object will float. If the buoyant force is less than the weight of the object, the object will sink.

Applications: Archimedes' principle has many applications, including the design of ships, submarines, and hot air balloons.

Example:

Imagine a block of wood floating in a pool of water. The water exerts an upward buoyant force on the block. The buoyant force is equal to the weight of the water that the block displaces. Since the block is floating, the buoyant force must be equal to the weight of the block.