Candlewax, a plastic solid with a low melting pointBesides their chemical make-up (what kind of atoms they have), solid materials have different qualities or properties. These include, for example, whether they are hard or soft, heavy or light, or shiny or dull. Some materials are stronger than others. Some are denser (have more matter packed into them) than others. Some are more elastic (stretchy) than others. Some are more plastic (how much its shape can be changed) than others. Other properties are: how well the material conducts heat and electricity, whether it dissolves in liquid or not, and what its boiling and melting points are.
Many solid materials are not irregular lumps, but have fixed shapes. Their atoms or molecules are arranged in regular patterns, known as crystals. These have sharp edges and flat sides. Some solids, for example glass, have no regular pattern in their molecules.
Molecules of salt (pictured below, left) are are arranged in a regular pattern forming a cube. Salt crystals (below, right) are therefore cube-shaped.
Rubber is highly elastic, but at very low temperatures it becomes brittle. It shatters into fragments if tapped with a hammer.
Find the answer