FLOTATION
The Expedition Severn team are all wearing flotation jackets to help them in case they fall into the river. The materials that make up these jackets have to be low density so that they will float in water. Objects that have a density the same or higher than water will sink. The density of river water is not the same everywhere though. Sea-water and freshwater are actually of different densities because of the salt content in them. In this experiment, we’ll try to quantify what difference this makes.