Imagine two identically sized bags – one filled with feathers and the other filled with sand. It is obvious that the bag filled with sand is heavier. But why is that, when the feathers and sand take up the same space in the bag? The reason is density.
Density is how tightly packed atoms are in an object. The closer together the atoms are, the more of them fit into a space. In the example above, the bag full of sand is much heavier than the bag full of feathers because there are more atoms packed into the sand, i.e. the density of the sand is greater than the density of the feathers.
DENSITY xxx
In this chapter, you will learn to: / calculate, measure and investigate the densities of substances / explain flotation / investigate the relationship between mass, density and flotation.
In this chapter, you will learn to: / xx
Low density
High density :Fig. 26.1 The closer together the atoms in an object are, the higher its density ? TEST TUBE
1. Two identical boxes are placed at each end of a balanced see-saw. Explain what would happen if the following items were added to the boxes and why:
b. one box filled with 2 kg of bricks and the other filled with 2 kg of polystyrene foam pellets :Fig. 26.2
a. one box filled with books and the other filled with feathers