With properties of matter in mind, students with visual impairments will design a boat that will hold as much weight as possible.
Density measures the amount of matter in a given volume of an object. To find the density of an object, divide the object’s mass by its volume (D = m/v). Density is a physical property, which means it is same for one substance, no matter how much of a substance is measured. Fresh water always has a density of 1g per cubic centimeter; a cup of water in your hand and water from an entire river has same density.
A buoyant object floats. Buoyancy is also a physical property. Whether an object floats or sinks in liquid depends on the object’s density. If the object’s density is less than the density of the liquid, it will float. If the object’s density is greater than the liquid’s density, it will sink. Then, how does a ship, made of dense iron, float in water? Although iron is denser than water, a ship is not a solid chunk of metal. It has a lot of rooms and empty area filled with air. Therefore, a ship has a much lower density than a solid piece of metal the size of the ship. This makes the ship’s density less than water’s density.