Place some items inside water and observe whether they float or sink.
Choose some items and throw them into the water. Observe which ones among them float or sink. This ensemble of objects of different composition – wood, metal, plastic and rock- are at your disposal to be placed in water and check their buoyancy. As you see , according to the shape and kind of material, some float and others do not. Two different forces act on every object: their weight and the buoyancy force. The weight of the object depends on its density. The stone that floats does that because of its porosity, that is to say, it has a low density, even less than water. The buoyancy of the liquid is higher than the weight of the stone and it ascends to the surface. In every situation, bodies are on its break even point when its weight and the buoyancy are identical. But if the weight is much higher, the object sinks.
«Un problema de densidades» es un módulo de la Sala del Agua incluido dentro de la sección «Agua y ciencia»