08. Why things float

Outcomes:

> Explain what causes some objects to float

> To evaluate boat designs using the ideas of density

> To explain what density is and how it determines if an object floats in water

> To identify the size of forces on a floating object and sinking object

Key Words: Density, predictions, weight, force, upthrust

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Activity:

Will a 2.5 g ball of plasticine float or sink?

If it floats, can you make it sink?

If it sinks, can you make it float?

Activity: Density cubes - 10 cubes, all the same size, but made from different materials. Can you calculate their density and work out which ones will float and which will sink?