What do all materials around us have in common ? What makes one substance different from another ? There is an immense variety of materials in the world , with all their different properties . How is it created ? All matter is made up of particles . The particles of matter are in constant motion , and forces are at work between them . The particulate structure of matter enables us to explain different phenomena in the material world , such as the dispersion of the scent of perfume in a room , the elongation of a metal bar upon heating , and condensation of water . The particulate structure of matter also explains the common properties of gases , liquids and solids , and the differences between them . In this chapter we will take a closer look at the mysteries of the particles of matter , and we will ask ourselves : What are those particles ? How can we use them to explain the variations between different materials or the immense diversity of materials in the world ? We will also learn ...  אל הספר
מטח : המרכז לטכנולוגיה חינוכית