Matter is defined as anything that has mass and takes space. It is everything around us. Rocks, oceans, plants, animals, houses and cars are all examples of matter. Although matter appears to be continuous and unbroken, it is not so. According to the ancient Greek Philosopher Democritus (470- 370 BC) matter is actually composed of discrete tiny particles called atoms, derived from the Greek word atoms, meaning "indivisible" (Image 1) . Atoms may not be visible to the macroscopic eye, however, modern instrumental techniques available today such as X-ray diffraction and scanning tunneling microscopy show the position of individual atoms (Image 2).
(Image 1) A penny is made up of copper atoms packed tightly together.
(Image 2) Individual atoms can be seen as bumps on the surface of a solid by scanning tunneling microscopy. This is an image of the surface of copper.
You may remember from your ordinary level work that a purple solution is formed when a crystal of potassium permanganate (KMnO4) is placed in a beaker of water. This observation can be explained by the particulate nature of matter. Both the crystal and water are made up of particles. These particles mix together and as a result a coloured solution is produced. The movement of different particles among each other is called diffusion. (Image 3) will further illustrate this phenomenon.
(Image 3) Mixing of potassium permanganate particles with water particles to give a coloured solution.
0 comments: