Forces - part 2 

In the infant and junior classes, children will develop their ideas about why some things float and others sink in water. Children in junior and in middle classes should discover through their practical investigations that buoyancy depends on a combination of factors, such as the material the object is made of, its shape, and the liquid in which it is placed. Children will discover that a material that normally sinks can be made to float by forming it into a hollow shape.

There is no effort at this stage to provide children with an understanding of the concept of density. Some children may develop their own ideas that an object floats if it is lighter or less dense than an identical amount (volume) of water and sinks if it is denser. However, work on the density of different liquids and displacement will be more appropriate to the post-primary curriculum.