Matter

States of aggregation: solid

A substance in a solid state can adopt different crystalline structures, which correspond to more than one way in which the atoms come together.

According to the conditions, snowflakes can adopt shapes like those shown below:

Crystalline substances which are soluble in water crystallize once more when it evaporates. This is not a change of state, but a crystallization, a way of obtaining beautiful crystals.

Activity

Dissolve a handful of cooking salt or copper sulphate which is used to spray plants, in a glass of water and shake and heat it gently. If some does not dissolve, filter it using a funnel and a filter paper like those used in some coffee machines. Wash your hands and the material you have used thoroughly after touching the copper sulphate.

Leave the dissolution in a wide glass, covered with a piece of paper so that the water slowly evaporates. A few days later when the water has totally evaporated, you will see some beautiful crystals.

	Solid
	Liquid
	Gas
	Plasma
	Changes of state

	The attraction between masses
	The effects of gravity
	Electric charge