What is The Difference Between Weight and Mass? (https://www.physlink.com/Education/AskExperts/ae321.cfm): This article uncovers the actual differences between weight and mass. Mass is a measure of how much matter an object has. Weight is a measure of how strongly gravity pulls on that matter. If you were to go to the moon, your weight would change but your mass would stay the same!
Science Project: Why Salt Makes Things Float (https://sciencing.com/science-project-salt-things-float-16667.html): Adding salt increases the density of water. As the salt dissolves in the water, the ions fit into spaces between the water molecules The mass of the saltwater is much higher and the volume only slightly greater, so the saltwater is more dense than freshwater. If the same volume of water is displaced by an object, the weight of the salt water displaced is greater, thus the force of buoyancy is proportionally greater.
Quick Facts on Icebergs (https://nsidc.org/cryosphere/quickfacts/icebergs.html): Icebergs come in all shapes and sizes, from ice-cube-sized chunks to ice islands the size of small countries. Icebergs from when chunks of ice break off from glaciers, ice shelves and travel with ocean currents. Icebergs pose danger to travelling ships. After the Titanic sank in 1912, the United States and 12 other countries formed the International Ice Patrol to warn ships of icebergs in the North Atlantic.
How Submarines Work (https://science.howstuffworks.com/transport/engines-equipment/submarine1.htm): A submarine can float because the weight of water that it displaces is equal to the weight of the ship. This displacement of water creates an upward force called buoyancy and acts opposite to gravity which is pulling the ship down. Unlike a ship, a submarine can control its buoyancy, allowing it to sink and surface at will. To control its buoyancy, the submarine has ballast tanks that can be filled with water or air depending on if it wants to go up or down.
