what are the applications of archimedes principle in every day life

  Archimedes’ principle is also used in designing ships and submarines.

The floating of a big ship is based on the Archimedes' principle. An iron nail sinks because it has more weight than the weight of the water it displaces. In other words, the density of the iron nail is greater than the density of water. In case of a ship, a large portion of it is hollow inside. This reduces the apparent density of the ship to a value less than the density of water. The weight of the water displaced by the ship is much more than its own weight. This makes the ship float on water.

A submarine can dive into the water or rise to the surface as needed. The most important compartments of a submarine that help in its floatation are the ballast tank, and the compressed air tank. To dive, the ballast tanks are filled with water so that the average density of the submarine becomes greater than the density of sea water, and the submarine dives. To rise, the water from the ballast tanks is forced out into the sea by allowing air from the compressed air tank to enter the ballast tank. As a result, the average density of the submarine decreases, and the submarine rises.

2. Fish float based on Archimedes' principle. Most fish have an organ known as the swim bladder. When they want to rise, fish release gas into the swim bladder and increase their volume. As a result, they displace more water. The force of buoyancy acting on them increases. To come down, a fish empties the bladder to the required extent, reducing the volume and the force of buoyancy acting on it.

3. A hot air balloon rises and floats due to the buoyant force (when the surrounding air is greater than its weight). It descends when the balloon's weight is higher than the buoyant force. It becomes stationary when the weight equals the buoyant force.
The weight of the Hot-air balloon can be controlled by varying the quantity of hot air in the balloon.

4. A hydrometer uses Archimedes’ principle to determine the density of any liquid.