What are things that will float in water?

Answer 1

This is easy.

A block of tungsten, iron, nickel, aluminum, titanium, gold, silver, zinc, copper, or magnesium will all sink in water. As you can see, I'm partial to metals. There are lots of nonmetallic substances that sink in water as well. Diamonds, carbon fiber composites, acrylonitrile butadiene styrene, polycarbonate, polyvinyl chloride, silica, sodium chloride, gypsum, etc. Neoprene rubber sinks in water.

On the other hand, a block of poplar, cedar, cherry, dogwood, pine, maple, oak, fir, hickory, or walnut will all float on water. There are some hardwoods that sink in water, such as ironwood, however, most wood species will float. Some polymer materials, like polyethylene, polystyrene, polypropylene, etc will also float on water. Natural rubber floats on water.

These lists are by no means exhaustive, but we can see that metals are generally denser than water while woods are generally less dense than water, and engineered plastic and rubber compounds can vary greatly in density, being denser than, or less dense than water.

Answer 2

Items that are less dense than water will float, such as wood, plastic, cork, and foam. Other examples include some fruits (like apples and Oranges), rubber, and some metals (like aluminum and titanium).